atomic See also:

• WEIGHT

weight 55.85 See also:

• atomic weight 55.85 IRON [symbol Fe (0=16)]

IRON [See also:

• SYMBOL (Gr. o-uµ(3oXov, a sign)

symbol Fe (0=16)]  , a metallic chemical See also:

• ELEMENT (Lat. elementum)

element . Although See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron occurs only sparingly in the See also:

• FREE

free See also:

• STATE
• STATE, GREAT OFFICERS OF

state, the abundance of ores from which it may be readily obtained led to its application in the arts at a very remote See also:

• PERIOD
• PERIOD (Gr. irepioSos, a going or way round, circuit, aepi, round, and &Sis, way, road)

period, It is generally agreed, however, that the Iron See also:

• AGE (Fr. age, through late Lat. aetaticum, from aetas)

Age, the period of See also:

• CIVILIZATION

civilization during which this See also:

• METAL
• METAL (through Fr. from Lat. metallum, mine, quarry, adapted from Gr. µATaXAov, in the same sense, probably connected with ,ueraAAdv, to search after, explore, µeTa, after, aAAos, other)

metal played an all-important See also:

• PART

part, succeeded the ages of See also:

• COPPER (symbol Cu, atomic weight 63.1, H=1, or 63.6, O = 16)

copper and See also:

• BRONZE

bronze, notwithstanding the fact that the extraction of these metals required greater metallurgical skill . The Assyrians and Egyptians made considerable use of the metal; and in See also:

• GENESIS
• GENESIS (Gr. 'ybeo-es, becoming; the term being used in English as a synonym for origin or process of coming into being)

Genesis iv . 22 mention is made of Tubal-See also:

• CAIN

cain as the instructor of workers in iron and copper . The earlier See also:

• SOURCES

sources of the ores appear to have been in See also:

• INDIA
• INDIA, FRENCH

India; the Greeks, however, obtained it from the Chalybes, who dwelt on the See also:

• SOUTH
• SOUTH, ROBERT (1634–1716)

south See also:

• COAST (from Lat. costa, a rib, side)

coast of the See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

Black See also:

• SEA (in O. Eng. sae, a common Teutonic word; cf. Ger. See, Dutch Zee, &c.; the ultimate source is uncertain)
• SEA, COMMAND OF THE

Sea; and the See also:

• ROMANS
• ROMANS, EPISTLE TO THE

Romans, besides See also:

• DRAWING

drawing from these deposits, also exploited See also:

• SPAIN
• SPAIN (Espana)

Spain, See also:

• ELBA (Gr. AiWaXla; Lat. Ilva)

Elba and the See also:

• PROVINCE
• PROVINCE (Lat. provincia; perhaps a contraction of providentia)

province of See also:

• NORICUM (Noricus ager)

Noricum . (See METAL-See also:

• WORK

WORK.) The See also:

• CHIEF (from Fr. chef, head, Lat. caput)

chief occurrences of metallic iron are as See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute spiculae disseminated through basaltic rocks, as at See also:

• GIANT (O.E. geant, through Fr. giant, O.Fr. gaiant, jaiant, jeant, med. pop. Lat. gagante—cf. Ital. gigante—by assimilation from gigantem, ace. of Lat. gigas, Gr. yiyas)

Giant's See also:

• CAUSEWAY

Causeway and in the See also:

• AUVERGNE

Auvergne, and, more particularly, in meteorites (q.v.) . In See also:

• COMBINATION (Lat. combinare, to combine)

combination it occurs, usually in small quantity, in most natural See also:

• WATERS, TERRITORIAL

waters, in See also:

• PLANTS

plants, and as a necessary constituent of See also:

• BLOOD

blood . The economic sources are treated under IRON AND See also:

• STEEL, FLORA ANNIE (1847– )

STEEL below; in the same See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place will be found accounts of the manufacture, properties, and uses of the metal, the See also:

• PRESENT

present See also:

• ARTICLE (from Lat. articulus, a joint)

article being confined to its See also:

• CHEMISTRY
• CHEMISTRY (formerly "chymistry"; Gr. xvµela; for derivation see ALCHEMY)

chemistry . The See also:

• PRINCIPAL

principal iron ores are the oxides and See also:

• CARBONATES

carbonates, and these readily yield the metal by smelting with See also:

• CARBON (symbol C, atomic weight 12)

carbon . The metal so obtained invariably contains a certain amount of carbon, free or combined, and the proportion and See also:

• CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition regulate the properties of the metal, giving origin to the three important varieties: See also:

• CAST (from the verb meaning " to throw "; the word is Scand. in origin, cf. Dan. kaste, and Swed. kasta; " cast " in Middle Eng. took the place of the A.S. weor pan, cf. Ger. werf en)

cast iron, steel, wrought iron . The perfectly pure metal may be prepared by See also:

• HEATING

heating the See also:

• OXIDE

oxide or oxalate in a current of See also:

• HYDROGEN [symbol H, atomic weight x-oo8 (0=16)]

hydrogen; when obtained at a See also:

• LOW, SETH (1850- )
• LOW, WILL HICOK (1853- )

low temperature it is a black See also:

• POWDER (through O. Fr. puldre, modern poudre, from Lat. pulvis, pulveris, dust)

powder which oxidizes in See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air with incandescence; produced at higher temperatures the metal is not pyrophoric . Peligot obtained it as minute tetragonal octahedra and cubes by reducing ferrous chloride in hydrogen .

It may be obtained electrolytically from solutions of ferrous and See also:

• MAGNESIUM [symbol Mg, atomic weight 24.32 (0 = 16)]

magnesium sulphates and See also:

• SODIUM [symbol Na, from Lat. natrium; atomic weight 23.00 (0=16)]

sodium bicarbonate, a wrought iron anode and a rotating See also:

• CATHODE

cathode of copper, thinly silvered and iodized, being employed (S . Maximowitsch, Zeit . Elektrochem., 1905, II, p . 52) . In bulk, the metal has a silvery See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white lustre and takes a high See also:

• POLISH

polish . Its specific gravity is 7.84; and the See also:

• AVERAGE

average specific See also:

• HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

heat over the range 15°–roo° is 0.10983; this value increases with temperature to 85o°, and then begins to diminish . It is the most tenacious of all the ductile metals at See also:

• ORDINARY (med. Lat. ordinarius, Fr. ordinaire)

ordinary temperatures with the exception of See also:

• COBALT (symbol Co, atomic weight 59)

cobalt and See also:

• NICKEL
• NICKEL (symbol Ni, atomic weight 58.68 (0=16))

nickel; it becomes brittle, however, at the temperature of liquid air . It softens at a red heat, and may be readily welded at a white heat; above this point it becomes brittle . It fuses at about 1550°°–1600°, and may be distilled in the electric See also:

• FURNACE

furnace (H . See also:

• MOISSAN, HENRI (1852-1907)

Moissan, Comp. rend., 19(36, 142, p . 425) . It is attracted by a magnet and may be magnetized, but the magnetization is quickly lost .

The variation of See also:

• PHYSICAL

physical properties which attends iron on heating has led to the view that the metal exists in allotropic fo ms (see IRON AND STEEL, below) . Iron is very reactive chemically . Exposed to atmospheric influences it is more or less rapidly corroded, giving the See also:

• FAMILIAR (through the Fr. familier, from Lat. familiaris, of or belonging to the familia, family)

familiar See also:

• RUST (O.E. rust, a word which appears in -many Teutonic languages, cf. Du. roest, Ger. rost); in origin it is allied with " ruddy " and " red," the reddish-brown powdery substance which forms on the surface of iron or steel exposed to atmospheric corrosio

rust (q.v.) . S . Burnie (Abst . J.C.S., 1907, H. p . 469) has shown that See also:

• WATER

water is decomposed at all temperatures from o' to See also:

• ROC

roc° by the finely divided metal with liberation of hydrogen, the See also:

• ACTION

action being accelerated when oxides are present . The de-See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

composition of See also:

• STEAM
• STEAM (0. Eng. steam, vapour, smoke, cf. Du. steam; the origin is unknown)

steam by passing it through a red-hot See also:

• GUN

gun-See also:

• BARREL (a word of uncertain origin common to Romance languages; the Celtic forms, as in the Gaelic baraill, are derived from the English)

barrel. resulting in the liberation of hydrogen and the See also:

• PRODUCTION (Lat. productionem, from producere, to pro-duce)

production of magnetic iron oxide, Fe304, is a familiar laboratory method for preparing hydrogen (q.v.) . When strongly heated iron inflames in See also:

• OXYGEN (symbol 0, atomic weight 16)

oxygen and in See also:

• SULPHUR

sulphur vapour; it also combines directly with the See also:

• HALOGENS

halogens . It dissolves in most dilute acids with liberation of hydrogen; the reaction. between sulphuric See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid and iron turnings being used for the commercial manufacture of this See also:

• GAS

gas . It dissolves in dilute See also:

• COLD (in O. Eng. cald and ceald, a word coming ultimately from a root cognate with the Lat. gelu, gelidus, and common in the Teutonic languages, which usually have two distinct forms for the substantive and the adjective, cf. Ger. Kolte, kalt, Dutch koude

cold nitric acid with the formation of ferrous and ammonium nitrates, no gases being liberated; when heated or with stronger acid ferric nitrate is formed with See also:

• EVOLUTION

evolution of See also:

• NITROGEN [symbol N., atomic weight 14.01, 0=16]

nitrogen oxides . It was observed by See also:

• JAMES
• JAMES (Gr. 'IlrKw,l3or, the Heb. Ya`akob or Jacob)
• JAMES (JAMES FRANCIS EDWARD STUART) (1688-1766)
• JAMES, 2ND EARL OF DOUGLAS AND MAR(c. 1358–1388)
• JAMES, DAVID (1839-1893)
• JAMES, EPISTLE OF
• JAMES, GEORGE PAYNE RAINSFOP
• JAMES, HENRY (1843— )
• JAMES, JOHN ANGELL (1785-1859)
• JAMES, THOMAS (c. 1573–1629)
• JAMES, WILLIAM (1842–1910)
• JAMES, WILLIAM (d. 1827)

James Keir (Phil .

Trans., 1790, p . 359) that iron, after having been immersed in strong nitric acid, is insoluble in acids, neither does it precipitate metals from solutions . This " passivity " may be brought about by See also:

• IMMERSION (Lat. immersio, dipping),

immersion in other solutions, especially by those containing such oxidizing anions as \O'3, C10'3, less strongly by the anions ti0"a, CV', CNS', C2H30'2, OH', while Cl', Br' practically inhibit passivity; H' is the only cation which has any effect, and this tends to exclude passivity . It is also occasioned by anodic polarization of iron in sulphuric acid . Other metals may be rendered passive; for example, See also:

• ZINC

zinc does not precipitate copper from solutions of the See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double cyanides and sulphocyanides, nickel and See also:

• CADMIUM (symbol Cd, atomic weight 112.4 (0=16))

cadmium from the nitrates, and iron from the sulphate, but it immediately throws down nickel and cadmium from the sulphates and chlorides, and See also:

• LEAD
• LEAD (pronounced iced)

lead and copper from the 'citrates (see O . Sackur, Zeit . Elektroc{tem., 1904, 10, p . 841). lnodic polarization in See also:

• POTASSIUM [symbol K (from kalium), atomic weight 39.114 0=16)]

potassium chloride See also:

• SOLUTION (from Lat. solvere, to loosen, dissolve)

solution renders See also:

• MOLYBDENUM [symbol, Mo; atomic weight, 96 (0=16)]

molybdenum, niobium, See also:

• RUTHENIUM [symbol Ru, atomic weight 101.7 (0=16)]

ruthenium, See also:

• TUNGSTEN [symbol W, atomic weight 184.o (0=16)]

tungsten, and See also:

• VANADIUM

vanadium passive (W . Muthmann and F . Frauenberger, Sitz . Bayer . 1kad .

11'iss., 1904, 34, p . 201), and also See also:

• GOLD
• GOLD [symbol Au, atomic weight 195.7(H = 1),197.2(0 =16)]

gold in commercial potassium See also:

• CYANIDE

cyanide solution (A . Coehn and C . L . See also:

• JACOBSEN, JENS PETER (1847-1885)

Jacobsen, albs . J.C.S., 1907. ii. p . 926) . Several hypotheses have been promoted to explain this behaviour, and, although the question is not definitely settled, the more probable view is that it is caused by the formation of a film of an oxide, a See also:

• SUGGESTION

suggestion made many years ago by See also:

• FARADAY, MICHAEL (1791-1867)

Faraday (see P . Krassa, Zeit . Elektrochem., 10o9, 15, p . 490) . Fredenhagen (Zell. physik .

Chem., 1903, 43, p . 1), on the other See also:

• HAND
• HAND (a word common to Teutonic languages; cf. Ger. Hand, Goth. handus)
• HAND, FERDINAND GOTTHELF (1786-185r)

hand, regarded it as due to See also:

• SURFACE

surface films of a gas; submitting that the difference between iron made passive by nitric acid and by anodic polarization was explained by the film being of nitrogen oxides in the first See also:

• CASE
• CASE, JOHN (d. 1600)

case and of oxygen in the second case . H . L . See also:

• HEATHCOTE, SIR GILBERT (c. 1651-1733)

Heathcote and others regard the passivity as invariably due to electrolytic action (see papers in the Zeit. physik . Chem., 1901 et seq.) . Compounds of Iron . Oxides and Hydroxides.—Iron forms three oxides: ferrous oxide, FeO, ferric oxide, Fe203, and ferroso-ferric oxide, Fe304. l'he first two give origin to well-defined See also:

• SERIES (a Latin word from serere, to join)

series of salts, the ferroussalts, wherein the metal is divalent, and the ferric salts, wherein the metal is trivalent; the former readily pass into the latter on oxidation, and the latter into the former on reduction . Ferrous oxide is obtained when ferric oxide is reduced in hydrogen at 300° as a black pyrophoric powder . See also:

• SABATIER, LOUIS AUGUSTE (1839-1901)

Sabatier and Senderens (Compt. rend., 1892, 114, p . 1429) obtained it by acting with nitrous oxide on metallic iron at 200°, and Tissandier by heating the metal to 900° in carbon dioxide; Donau (Monats., 1904, 25, p . 18t), on the other hand, obtained a magnetic and crystalline-ferroso-ferric oxide at 120o° .

It may also be prepared as a black velvety powder which readily takes up oxygen from the air by adding ferrous oxalate to boiling See also:

• CAUSTIC (Gr. rcavvraubs, burning)

caustic potash . Ferrous See also:

• HYDRATE

hydrate, Fc(OH)2, when prepared from a pure ferrous See also:

• SALT (a common Teutonic word, cf. Dutch zout, Ger. Salz, Scand. salt; cognate with Gr. &Xs, Lat. sal)
• SALT, SIR TITUS, BART

salt and caustic soda or potash free from air, is a white powder which may be preserved in an See also:

• ATMOSPHERE (Gr. fir µ6r, vapour; orkaipa, a sphere)

atmosphere of hydrogen . Usually, however, it forms a greenish See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass, owing to partial oxidation . It oxidizes on exposure with considerable evolution of heat; it rapidly absorbs carbon dioxide; and readily dissolves in acids to See also:

• FORM (Lat. forma)

form ferrous salts, which are usually white when anhydrous, but greenish when hydrated . Ferric oxide or iron sesquioxide, Fe203, constitutes the valuable ores red See also:

• HAEMATITE, or HEMATITE

haematite and specular iron; the minerals See also:

• BROWN
• BROWN, CHARLES BROCKDEN (1771-181o)
• BROWN, FORD MADOX (1821-1893)
• BROWN, FRANCIS (1849- )
• BROWN, GEORGE (1818-188o)
• BROWN, HENRY KIRKE (1814-1886)
• BROWN, JACOB (1775–1828)
• BROWN, JOHN (1715–1766)
• BROWN, JOHN (1722-1787)
• BROWN, JOHN (1735–1788)
• BROWN, JOHN (1784–1858)
• BROWN, JOHN (1800-1859)
• BROWN, JOHN (1810—1882)
• BROWN, JOHN GEORGE (1831— )
• BROWN, ROBERT (1773-1858)
• BROWN, SAMUEL MORISON (1817—1856)
• BROWN, SIR GEORGE (1790-1865)
• BROWN, SIR JOHN (1816-1896)
• BROWN, SIR WILLIAM, BART
• BROWN, THOMAS (1663-1704)
• BROWN, THOMAS (1778-1820)
• BROWN, THOMAS EDWARD (1830-1897)
• BROWN, WILLIAM LAURENCE (1755–1830)

brown haematite or See also:

• LIMONITE, or BROWN IRON ORE

limonite, and See also:

• GOTHITE

gothite and also iron rust are hydrated forms . It is obtained as a steel-See also:

• GREY, CHARLES GREY, 2ND EARL (1764-1845)
• GREY, HENRY GREY, 3RD EARL (1802-1894)
• GREY, LADY JANE (1537-1554)
• GREY, SIR EDWARD
• GREY, SIR GEORGE (1812–1898)

grey crystalline powder by igniting the oxide or any ferric salt containing a volatile acid . Small crystals are formed by passing ferric chloride vapour over heated See also:

• LIME
• LIME (O. Eng. lim, Lat. limes, mud, from linere, to smear)

lime . When finely ground these crystals yield a brownish red powder which dissolves slowly in acids, the most effective solvent being a boiling mixture of 8 parts of sulphuric acid and 3 of water . Ferric oxide is employed as a pigment, as jeweller's See also:

• ROUGE (" red," from Lat. rubeus)

rouge, and'for polishing metals . It forms several hydrates, the medicinal value of which was recognized in very remote times . Two series of synthetic hydrates were recognized by Muck and Tommasi: the " red " hydrates, obtained by precipitating ferric salts with alkalis, and the " yellow " hydrates, obtained ,by oxidizing moist ferrous hydroxide or carbonates . J. See also:

• VAN

van Bemmelen has shown that the red hydrates are really colloids, the amount of water retained being such that its vapour pressure equals the pressure of the aqueous vapour in the superincumbent atmosphere .

By heating freshly prepared red ferric hydrate with water under 5000 atmospheres pressure See also:

• RUFF

Ruff (Ber., 19o1, 34, p . 3417) obtained definite hydrates corresponding to the minerals limonite (3o0-42.50), gothite (42.5°–62.5°), and hydrohaematite (above 62.5°) . See also:

• THOMAS
• THOMAS (c. 1654-1720)
• THOMAS (d. 110o)
• THOMAS, ARTHUR GORING (1850-1892)
• THOMAS, CHARLES LOUIS AMBROISE (1811-1896)
• THOMAS, GEORGE (c. 1756-1802)
• THOMAS, GEORGE HENRY (1816-187o)
• THOMAS, ISAIAH (1749-1831)
• THOMAS, PIERRE (1634-1698)
• THOMAS, SIDNEY GILCHRIST (1850-1885)
• THOMAS, ST
• THOMAS, THEODORE (1835-1905)
• THOMAS, WILLIAM (d. 1554)

Thomas See also:

• GRAHAM, SIR GERALD (1831–1899)
• GRAHAM, SIR JAMES ROBERT GEORGE
• GRAHAM, SYLVESTER (1794-1851)
• GRAHAM, THOMAS (1805-1869)

Graham obtained a soluble hydrate by dissolving the freshly prepared hydrate in ferric chloride and dialysing the solution, the soluble hydrate being See also:

• LEFT

left in the dialyser . All the See also:

• CHLORINE (symbol Cl, atomic weight 35`46 (0=16)

chlorine, however, does not appear to be removed by this See also:

• PROCESS

process, the See also:

• RESIDUE (through the French, from the Lat. residuum, a remainder, from residere, to remain)

residue having the composition 82Fe(OH)a.FeC13; but it may be by electrolysing in a porous See also:

• CELL (from Lat. cella, probably from an Indo-European kal —seen in Lat. celare, to hide; another suggestion connects the word with Lat. cera, wax, taking the original meaning to refer to the honeycomb)

cell (Tribot and Chretien, See also:

• CORN (a common Teutonic word; cf. Lat. granum, seed, grain)
• CORN (fromm Lat. corms, horn)

Corn pi. rend., 1905, 140, p . 144) . On See also:

• STANDING

standing, the solution usually gelatinizes, a process accelerated by the addition of an electrolyte . It is employed in See also:

• MEDICINE

medicine under the name Liquor See also:

• FERRI, CIRO (1634-1689)
• FERRI, LUIGI (1826-1895)

ferri dialysati . The, so-called soluble See also:

• META

meta-ferric hydroxide, FeO(OH) (?), discovered by Nan de St Gilles in 1856, may be obtained by several methods . By heating solutions of certain iron salts for some See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time and then adding a little sulphuric acid it is precipitated as a brown powder . Black scales, which dissolve in water to form a red solution, are obtained by adding a trace of hydrochloric acid to a solution of basic ferric nitrate which has been heated to too° for three days . A similar See also:

• COMPOUND
• COMPOUND (from Lat. componere, to combine or put together)

compound, which, however, dissolves in water to form an See also:

• ORANGE
• ORANGE (Citrus Aurantium)
• ORANGE, HOUSE OF

orange solution, results by adding salt to a heated solution of ferric chloride . These compounds are insoluble in concentrated, but dissolve readily in dilute acids .

Red ferric hydroxide dissolves in acids to form a well-defined series of salts, the ferric salts, also obtained by oxidizing ferrous salts; they are usually colourless when anhydrous, but yellow or brown when hydrated . It has also feebly acidic properties, forming ferrites with strong bases . See also:

• MAGNETITE

Magnetite, Fe304, may be regarded as ferrous ferrite, FeO•Fe2O3 . This important ore of iron is most celebrated for its magnetic properties (see See also:

• MAGNETISM
• MAGNETISM, TERRESTRIAL

MAGNETISM and See also:

• COMPASS (Fr. corn pas, ultimately from Lat. cum, with, and passus, step)

COMPASS), but the See also:

• MINERAL

mineral is not always magnetic, although invariably attracted by a magnet . It may be obtained artificially by passing steam over red-hot iron . It dissolves in acids to form a mixture of a ferrous and ferric salt,' and if an See also:

• ALKALI

alkali is added to the solution a black precipitate is obtained which dries to a dark brown mass of the composition Fe(OH)2•Fe203; this substance is attracted by a magnet, and thus may be separated from the admixed ferric oxide . See also:

• CALCIUM [symbol Ca, atomic weight 40.0 (o= x6)]

Calcium ferrite, magnesium ferrite and zinc ferrite, RO•Fe2O3 (R=Ca, Mg, Zn), are obtained by intensely heating mixtures of the oxides; magnesium ferrite occurs in nature as the mineral magnoferrite, and zinc ferrite as See also:

• FRANKLINITE

franklinite, both forming black octahedra . Ferric acid, H2FeO4 . By fusing iron with See also:

• SALTPETRE (from the Lat. sal, salt, Petra, a rock)

saltpetre and extracting the melt with water, or by adding a solution of ferric nitrate in nitric acid to strong potash, an See also:

• AMETHYST

amethyst or See also:

• PURPLE

purple-red solution is obtained which contains potassium ferrate . E . See also:

• FREMY, EDMOND (1814–1894)

Fremy investigated this See also:

• DISCOVERY

discovery, made by See also:

• STAHL, FRIEDRICH JULIUS (1802-1861)
• STAHL, GEORG ERNST (1660-1734)

Stahl in 1702, and showed that the same solution resulted when chlorine is passed into strong potash solution containing ferric hydrate in suspension . Haber and Pick (Zeit .

Elektrochem., 1900, 7, p . 215) have prepared potassium ferrate by electrolysing concentrated potash solution, using an iron anode . A temperature of 70°, and a reversal of the current (of low See also:

• DENSITY (Lat. densus, thick)

density) between two cast iron electrodes every few minutes, are the best working conditions . When concentrated the solution is nearly black, and on heating it yields a yellow solution of potassium ferrite, oxygen being evolved . See also:

• BARIUM (symbol Ba, atomic weight 137'37 [0=16])

Barium ferrate, BaFeO4•See also:

• H2O (combined)

H2O, obtained as a dark red powder by adding barium chloride to a solution of potassium ferrate, is fairly See also:

• STABLE

stable . It dissolves in acetic acid to form a red solution, is not decomposed by cold sulphuric acid, but with hydrochloric or nitric acid it yields barium and ferric salts, with evolution of chlorine or oxygen (Baschieri, See also:

• GAZETTE

Gazette, 1906, 36, ii. p . 282) . Halogen Compounds.—Ferrous fluoride, FeF2, is obtained as colourless prisms (with 8H20) by dissolving iron in hydrofluoric acid, or as anhydrous colourless rhombic prisms by heating iron or ferric chloride in dry hydrofluoric acid gas . Ferric fluoride, FeF3, is obtained as colourless crystals (with 41H2O) by evaporating a solution of the hydroxide in hydrofluoric acid . When heated in air it yields ferric oxide . Ferrous chloride, FeCl2, is obtained as shining scales by passing chlorine, or, better, hydrochloric acid gas, over red-hot iron, or by reducing ferric chloride in a current of hydrogen . It is very deliquescent, and freely dissolves in water and See also:

• ALCOHOL

alcohol .

Heated in air it yields a mixture of ferric oxide and chloride, and in steam magnetic oxide, hydrochloric acid, and hydrogen . It absorbs See also:

• AMMONIA (NH3)

ammonia gas, forming the compound FeC12.6NH3, which on heating loses ammonia, and, finally, yields ammonium chloride, nitrogen and iron nitride . It fuses at a red-heat, and volatilizes at a yellow-heat; its vapour density at 1300°—1400° corresponds to the See also:

• FORMULA
• FORMULA (Lat. diminutive of forma, shape, pattern, &c., especially used of rules of judicial procedure)

formula FeC12 . By evaporating in vacuo the solution obtained by dissolving iron in hydrochloric acid, there results bluish, See also:

• MONOCLINIC

monoclinic crystals of FeCl2.4H20, which deliquesce, turning greenish, on exposure to air, and effloresce in a desiccator . Other hydrates are known . By adding ammonium chloride to the solution, evaporating in vacuo, and then volatilizing the ammonium chloride, anhydrous ferrous chloride is obtained . The solution, in See also:

• COMMON

common with those of most ferrous salts, absorbs nitric oxide with the formation of a brownish solution . Ferric chloride, FeCl3, known in its aqueous solution to See also:

• GLAUBER, JOHANN RUDOLF (1604-1668)

Glauber as oleum martis, may be obtained anhydrous by the action of dry chlorine on the metal at a moderate red-heat, or by passing hydrochloric acid gas over heated ferric oxide . It forms iron-black plates or tablets which appear red by transmitted and a metallic See also:

• GREEN, A
• GREEN, ALEXANDER HENRY (1832—1896)
• GREEN, DUFF (1791—1875)
• GREEN, JOHN RICHARD (1837—1883)
• GREEN, MATTHEW (1696-1737)
• GREEN, THOMAS HILL (1836-1882)
• GREEN, VALENTINE (1739–1813)
• GREEN, WILLIAM HENRY (.1825–1900)

green by reflected See also:

• LIGHT

light . It is very deliquescent, and readily dissolves in water, forming a brown or yellow solution, from which several hydrates may be separated (see SOLUTION) . The solution is best prepared by dissolving the hydrate in hydrochloric acid and re-moving the excess of acid by evaporation, or by passing chlorine into the solution obtained by dissolving the metal in hydrochloric acid and removing the excess of chlorine by a current of carbon dioxide . It also dissolves in alcohol and See also:

• ETHER, (C2H5)2O

ether; boiling point determinations of the molecular See also:

• WEIGHT

weight in these solutions point to the formula FeC13 .

Vapour density determinations at 448° indicate a partial See also:

• DISSOCIATION

dissociation of the double See also:

• MOLECULE (from mod. Lat. molecula, the diminutive of moles, a mass)

molecule Fe2C16; on stronger heating it splits into ferrous chloride and chlorine . It forms red crystalline double salts with the chlorides of the metals of the alkalis and of the ' By solution in concentrated hydrochloric acid, a yellow liquid-is obtained, which on concentration over sulphuric acid gives yellow deliquescent crusts of ferroso-ferric chloride, Fe3CI4'1 -120.magnesium See also:

• GROUP

group . An aqueous solution of ferric chloride is used in See also:

• PHARMACY

pharmacy under the name Liquor ferri perchloridi; and an alcoholic solution constitutes the See also:

• QUACK

quack medicine known as " Lamotte's See also:

• GOLDEN

golden drops." Many oxychlorides are known; soluble forms are obtained by dissolving precipitated ferric hydrate in ferric chloride, whilst insoluble compounds result when ferrous chloride is oxidized in air, or by boiling for some time aqueous solutions of ferric chloride . Ferrous bromide, FeBr2, is obtained as yellowish crystals by the See also:

• UNION
• UNION (known locally as Union Hill and officially as Town of Union)

union of See also:

• BROMINE (symbol Br, atomic weight 79-96)

bromine and iron at a dull red-heat, or as bluish-green rhombic tables of the composition FeBr2.6H20 by crystallizing a solution of iron in hydrobromic acid . Ferric bromide, FeBr3, is obtained as dark red crystals by heating iron in an excess of bromine vapour . It closely resembles the chloride in being deliquescent, dissolving ferric hydrate, and in yielding basic salts . Ferrous iodide, FeI2, is obtained as a grey crystalline mass by the See also:

• DIRECT

direct union of its components . Ferric iodide does not appear to exist . Sulphur Compounds.—Ferrous sulphide, FeS, results from the direct union of its elements, best by stirring molten sulphur with a white-hot iron See also:

• ROD (O.E. rodd, probably related to Norw. rudda, stick, rodda, stake)
• ROD, EDOUARD (1857-1910)

rod, when the sulphide drops to the bottom of the crucible . It then forms a yellowish crystalline mass, which readily dissolves in acids with the liberation of sulphuretted hydrogen . Heated in air it at first partially oxidizes to ferrous sulphate, and at higher temperatures it yields sulphur dioxide and ferric oxide . It is unaltered by ignition in hydrogen .

An amorphous form results when a mixture of iron filings and sulphur are triturated with water . This modification is rapidly oxidized by the air with such an See also:

• ELEVATION

elevation of temperature that the mass may become incandescent . Another black amorphous form results when ferrous salts are precipitated by ammonium sulphide . Ferric sulphide, Fe2S3, is obtained by gently heating a mixture of its' constituent elements, or by the action of sulphuretted hydrogen on ferric oxide at temperatures below too° . It is also prepared by precipitating a ferric salt with ammonium sulphide; unless the alkali be in excess a mixture of ferrous sulphide and sulphur is obtained . It combines with other sulphides to form compounds of the type M'2Fe2S4 . Potassium ferric sulphide, K2Fe2S4, obtained by heating a mixture of iron filings, sulphur and potassium carbonate, forms purple glistening crystals, which See also:

• BURN, RICHARD (1709-1785)

burn when heated in air . Magnetic See also:

• PYRITES

pyrites or See also:

• PYRRHOTITE

pyrrhotite has a composition varying between Fe,S6 and Fe3S9, i.e . 5FeS•Fe2S3 and 6FeS•Fe2S3 . It has a some-what brassy See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour, and occurs massive or as hexagonal plates; it is attracted by a magnet and is sometimes itself magnetic . The mineral is abundant in See also:

• CANADA

Canada, where the presence of about 5 % of nickel makes it a valuable ore of this metal . Iron disulphide, FeS2, constitutes the minerals pyrite and See also:

• MARCASITE

marcasite (q.v.) copper pyrites is (Cu, Fe)S2 .

Pyrite may be prepared artificially by gently heating ferrous sulphide with sulphur, or as brassy octahedra and cubes by slowly heating an intimate mixture of ferric oxide, sulphur and sal-ammoniac . It is insoluble in dilute acids, but dissolves in nitric acid with separation of sulphur . Ferrous sulphite, FeSO3 . Iron dissolves in a solution of sulphur dioxide in the See also:

• ABSENCE (Lat. absentia)

absence of air to form ferrous sulphite and thiosulphate; the former, being less soluble than the latter, separates out as colourless or greenish crystals on standing . Ferrous sulphate, green See also:

• VITRIOL

vitriol or See also:

• COPPERAS (Fr. couperose; Lat. cupri rosa. the flower of copper)

copperas, FeSO4.7H2O, was known to, and used by, the alchemists; it is mentioned in the writings of See also:

• AGRICOLA (originally SCHNEIDER, then SCHNITTER), JOHANNES (1494-1566)
• AGRICOLA (the Latinized form of the name BAUER), GEORG (1490-1555)
• AGRICOLA, CHRISTOPH LUDWIG (1667-1719)
• AGRICOLA, GNAEUS JULIUS (A.D. 37-93)
• AGRICOLA, JOHANN FRIEDRICH (1720-1774)
• AGRICOLA, MARTIN (c. 1500-1556)
• AGRICOLA, RODOLPHUS (properly ROELOF HUYSMANN) (1443-1485)

Agricola, and its preparation from iron and sulphuric acid occurs in the Tractatus chymico-philosophicus ascribed to See also:

• BASIL (Russ. VASILY)

Basil See also:

• VALENTINE, or VALENTINUS

Valentine . It occurs in nature as the mineral melanterite, either crystalline or fibrous, but usually massive; it appears to have been formed by the oxidation of pyrite or marcasite . It is manufactured by piling pyrites in heaps and exposing to atmospheric oxidation, the ferrous sulphate thus formed being dissolved in water, and the solution run into tanks, where any sulphuric acid which may be formed is decomposed by adding scrap iron . By evaporation the green vitriol is obtained as large crystals . The chief impurities are copper and ferric sulphates; the former may be removed by adding scrap iron, which precipitates the copper; the latter is eliminated by recrystallization . Other impurities such as zinc and See also:

• MANGANESE (symbol Mn; atomic weight, 54.93 (0=16)], a metallic chemical element. Its dioxide (pyrolusite)

manganese sulphates are more difficult to remove, and hence to prepare the pure salt it is best to dissolve pure iron See also:

• WIRE (A.S. wir, a wire; cf. Swed. vire, to twist, M.H.G. wiere, a gold ornament, Lat. viriae, armlets, ultimately from the root wi, to twist, bind)

wire in dilute sulphuric acid . Ferrous sulphate forms large green crystals belonging to the mono-clinic See also:

• SYSTEM

system; rhombic crystals, isomorphous with zinc sulphate, are obtained by inoculating a solution with a crystal of zinc sulphate, and triclinic crystals of the formula FeSO4.5H20 by inoculating with copper sulphate . By evaporating a solution containing free See also:

• STILT

stilt phurie acid in a vacuum, the hepta-hydrated salt first separates, then the penta-, and then a tetra-hydrate, FeSO4.4H2O, isomorphous with manganese sulphate .

By gently heating in a vacuum to 14o°, the hepta-hydrate loses 6 molecules of water, and yields a white powder, which on heating in the absence of air gives the anhydrous salt . The monohydrate also results as a white precipitate when concentrated sulphuric acid is added to a saturated solution of ferrous sulphate . Alcohol also throws down the salt from aqueous solution, the composition of the precipitate varying with the amount of salt and precipitant employed . The solution absorbs nitric oxide to form a dark brown solution, which loses the gas on heating or by placing in a vacuum . Ferrous sulphate forms double salts with the alkaline sulphates . The most important is ferrous ammonium sulphate, FeSO4•(NH4)2SO4.6H20, obtained by dissolving See also:

• EQUIVALENT

equivalent amounts of the two salts in water and crystallizing . It is very stable and is much used in volumetric See also:

• ANALYSIS (Gr. avci and Meta, to break up into parts)

analysis . Ferric sulphate, Fe2(SO4)s, is obtained by adding nitric acid to a hot solution of ferrous sulphate containing sulphuric acid, colourless crystals being deposited on evaporating the solution . The an-hydrous salt is obtained by heating, or by adding concentrated sulphuric acid to a solution . It is sparingly soluble in water, and on heating it yields ferric oxide and sulphur dioxide . The mineral coquimbite is Fe2(SO4)3'9H20 . Many basic ferric sulphates are known, some of which occur as minerals; carphosiderite is Fe(FeO)s(SO4)4.1OH2O; amarantite is Fe(FeO) (SO4)2.7H20; utahite is 3(FeO)2SO4.4H20; copiapite is Fe3(FeO) (SO4)s•18H20; castanite is Fe(FeO) (SO4)2.8H2O; romerite is .FeSO4•Fe2(SO4)s•12H20 .

The iron alums are obtained by crystallizing solutions of equivalent quantities of ferric and an alkaline sulphate . Ferric potassium sulphate, the common iron See also:

• ALUM

alum, K2SO4•Fe2(SO4)s•24H2O, forms See also:

• BRIGHT, JOHN (1811-188g)
• BRIGHT, SIR CHARLES TILSTON

bright See also:

• VIOLET

violet octahedra . Nitrides, Nitrates, &c.—Several nitrides are known . Guntz (Compt. rend., 1902, 135, p . 738) obtained ferrous nitride, Fe3N2, and ferric nitride, FeN, as black powders by heating See also:

• LITHIUM [symbol Li, atomic weight 7•oo (0=16)]

lithium nitride with ferrous potassium chloride and ferric potassium chloride respectively . See also:

• FOWLER, CHARLES (1792-1867)
• FOWLER, EDWARD (1632-1714)
• FOWLER, JOHN (1826-1864)
• FOWLER, SIR JOHN (1817-1898)
• FOWLER, WILLIAM (c. 156o-1614)

Fowler (Jour . Chem . See also:

• SOC

Soc., 1901, p . 285) obtained a nitride Fe2N by acting upon anhydrous ferrous chloride or bromide, finely divided reduced iron, or iron See also:

• AMALGAM

amalgam with ammonia at 4200; and, also, in a compact form, by the action of ammonia on red-hot iron wire . It oxidizes on heating in air, and ignites in chlorine; on solution in mineral acids it yields ferrous and ammonium salts, hydrogen being liberated . A nitride appears to be formed when nitrogen is passed over heated iron, since the metal is rendered brittle . Ferrous nitrate, Fe(NO3)2.6H2O, is a very unstable salt, and is obtained by mixing solutions of ferrous sulphate and barium nitrate, filtering, and crystallizing in a vacuum over sulphuric acid .

Ferric nitrate, Fe(NO3)s, is obtained by dissolving iron in nitric acid (the cold dilute acid leads to the formation of ferrous and ammonium nitrates) and crystallizing, when cubes of Fe(NOs)s•6H20 or mono-clinic crystals of Fe(NO3)a•9H20 are obtained . It is used as a See also:

• MORDANT

mordant . Ferrous solutions absorb nitric oxide, forming dark green to black solutions . The coloration is due to the production of unstable compounds of the ferrous salt and nitric oxide, and it seems that in neutral solutions the compound is made up of one molecule of salt to one of gas; the reaction, however, is reversible, the composition varying with temperature, concentration and nature of the salt . Ferrous chloride dissolved in strong hydrochloric acid absorbs two molecules of the gas (Kohlschiitter and Kutscheroff, Ber., 1907, 40, p . 873) . Ferric chloride also absorbs the gas . Reddish brown amorphous powders of the fcrmulae 2FeC1s.NO and 4FeC13•NO are obtained by passing the gas over anhydrous ferric chloride . By passing the gas into an ethereal solution of the salt, nitrosyl chloride is produced, and on evaporating over sulphuric acid, black needles of FeCl2•NO.2H20 are obtained, which at 6o° form the yellow FeCl2'NO . Complicated compounds, discovered by Roussin in 1858, are obtained by the interaction of ferrous sulphate and alkaline nitrites and sulphides . Two classes may be distinguished:—(i) the ferrodinitroso salts. e.g . K[Fe(NO)2S], potassium ferrodinitrososulphide, and (2) the ferroheptanitroso salts, e.g .

K[Fes(NO)7Ss], potassium ferroheptanitrososulphidc . These salts yield the corresponding acids with sulphuric acid . The dinitroso acid slowly decomposes into sulphuretted hydrogen, nitrogen, nitrous oxide, and the heptanitroso acid . The heptanitroso acid is precipitated as a brown amorphous mass by dilute sulphuric acid, but if the salt be heated with strong acid it yields nitrogen, nitric oxide, sulphur, sulphuretted hydrogen, and ferric, ammonium and potassium sulphates . Phosphides, See also:

• PHOSPHATES

Phosphates.—H . Le Chatelier and S., Wologdine (Compt. rend., 1909, 149, p . 709) have obtained FesP, Fe2P, FeP, Fe2P3, but failed to prepare five other phosphides previously described . Fe3P occurs as crystals in the product of fusing iron with See also:

• PHOSPHORUS (Gr. 4ws, light, sPEpety, to bear)

phosphorus; it dissolves in strong hydrochloric acid . Fe2P forms crystalline needles insoluble in acids except aqua regia; it is obtained by fusing copper phosphide with iron . FeP is obtained by passing phosphorus vapour over Fe2P at a red-heat . Fe2P3 is prepared by the action of phosphorus iodide vapour on reduced iron . Ferrous phosphate, Fe3(PO4)2.8H20, occurs in nature as the mineral See also:

• VIVIANITE

vivianite .

It may be obtained artificially as a white precipitate, which rapidly turns See also:

• BLUE (common in different forms to most European languages)

blue or green on exposure, by mixing solutions of ferrous sulphate and sodium phosphate . It is employed in medicine . Normal ferric phosphate, FePO4.2H2O, occurs as the mineral strengite, and is obtained as a yellowish-white precipitate by mixing solutions of ferric chloride and sodium phosphate . It is insoluble in dilute acetic acid, but dissolves in mineral acids . The acid salts Fe(H2PO4)s and 2FeH3(PO4)2•5H20 have been described . Basic salts have been prepared, and several occur in the mineral See also:

• KINGDOM

kingdom; dufrenite is Fes(OH)3PO4 . A rsen ides, Arse See also:

• NILES

niles, &c.—Several iron arsenides occur as minerals; lolingite, FeAs2, forms silvery rhombic prisms; See also:

• MISPICKEL

mispickel or arsenical pyrites, Fe2AsS2, is an important commercial source of See also:

• ARSENIC (symbol As, atomic weight 75.0)

arsenic . A basic ferric arsenite, 4Fe2O3• A s203.5H2O, is obtained as a flocculent brown precipitate by adding an arsenite to ferric acetate, or by shaking freshly prepared ferric hydrate with a solution of arsenious oxide . The last reaction is the basis of the application of ferric hydrate as an antidote in arsenical poisoning . Normal ferric arsenate, FeAsO4•2H2O, constitutes the mineral scorodite; See also:

• PHARMACOSIDERITE

pharmacosiderite is the basic arsenate 2FeAsO4•Fe(OK)3.5H20 . An acid arsenate, 2Fe2(HAsOa)i.9H1O, is obtained as a white precipitate by mixing solutions of ferric chloride and ordinary sodium phosphate . It readily dissolves in hydrochloric acid .

Carbides, Carbonates.—The carbides of iron See also:

• PLAY

play an important part in determining the properties of the different modifications of the commercial metal, and are discussed under IRON AND STEEL . Ferrous carbonate, FeCO3, or spathic iron ore, may be obtained as microscopic rhombohedra by adding sodium bicarbonate to ferrous sulphate and heating to 15o° for 36 See also:

• HOURS, CANONICAL

hours . Ferrous sulphate and sodium carbonate in the cold give a flocculent precipitate, at first white but rapidly turning green owing to oxidation . A soluble carbonate and a ferric salt give a precipitate which loses carbon dioxide on drying . Of See also:

• GREAT

great See also:

• INTEREST

interest are the carbonyl compounds . Ferropentacarbonyl, Fe(CO)s, obtained by L . See also:

• MOND, LUDWIG (1839-1909)

Mond, Quincke and Langer (Jour . Chem . Soc., 1891; see also ibid . 1910, p . 798) by treating iron from ferrous oxalate with carbon monoxide, and heating at 15o°, is a See also:

• PALE (through Fr. pal, from Lat. palms, a stake, for paglus, from the stem pag- of pangere, to fix; " pole " is from the same original source)

pale yellow liquid which freezes at about -20°, and boils at 102.5° . Air and moisture decompose it .

The halogens give ferrous and ferric haloids and carbon monoxide; hydrochloric and hydrobromic acids have no action, but hydriodic decomposes it . By exposure to sunlight, either alone or dissolved in ether or ligroin, it gives lustrous orange plates of diferrononacarbonyl, Fe2(CO)i . If this substance be heated in ethereal solution to 5o°, it deposits lustrous dark-green tablets of ferrotetracarbonyl, Fe(CO)4, very stable at ordinary temperatures, but decomposing at 140°-15o° into iron and carbon monoxide (J . See also:

• DEWAR, SIR JAMES (1842- )

Dewar and H . 0 . See also:

• JONES
• JONES, ALFRED GILPIN (1824-1906)
• JONES, EBENEZER (182o-186o)
• JONES, ERNEST CHARLES (1819-1869)
• JONES, HENRY (1831-1899)
• JONES, HENRY ARTHUR (1851- )
• JONES, INIGO (1573-1651)
• JONES, JOHN (c. 1800-1882)
• JONES, MICHAEL (d. 1649)
• JONES, OWEN (1741-1814)
• JONES, OWEN (1809-1874)
• JONES, RICHARD (179o-1855)
• JONES, SIR ALFRED LEWIS (1845-1909)
• JONES, SIR WILLIAM (1746-1794)
• JONES, THOMAS RUPERT (1819– )
• JONES, WILLIAM (1726-1800)

Jones, Abst . J.C.S., 1907, ii . 266) . For the cyanides see PRUSSIC ACID . Ferrous salts give a greenish precipitate with an alkali, whilst ferric give a characteristic red one . Ferrous salts also give a bluish white precipitate with ferrocyanide, which on exposure turns to a dark blue; ferric salts are characterized by the intense purple coloration with a thiocyanate . (See also CHEMISTRY, § See also:

• ANALYTICAL

Analytical) .

For the quantitative estimation see See also:

• ASSAYING

ASSAYING . A See also:

• RECENT

recent atomic weight determination by See also:

• RICHARDS, ALFRED BATE (182o-1876)
• RICHARDS, HENRY BRINLEY (1819-1865)
• RICHARDS, WILLIAM TROST (1833-1905)

Richards and See also:

• BAXTER, ANDREW (1686-1750)
• BAXTER, RICHARD (1615-1691)
• BAXTER, ROBERT DUDLEY (1827-1875)
• BAXTER, WILLIAM (1650-1723)

Baxter (Zeit. anorg . Chem., 1900, 23, p . 245 ; 1904, 38, p . 232), who found the amount of See also:

• SILVER

silver bromide given by ferrous bromide, gave the value 5544 [0=16] . See also:

• PHARMACOLOGY

Pharmacology . All the See also:

• OFFICIAL (Late Lat. QJicialis, for class. Lat. apparitor, from officium, office, duty)

official salts and preparations of iron are made directly or indirectly from the metal . Thepharmacopoeial forms of iron are as follow: 1 . Ferrum, annealed iron wire No . 35 or wrought iron nails free from oxide; from which we have the preparation Vinum ferri, iron See also:

• WINE (Lat. vinum, Gr. oivos)

wine, iron digested in See also:

• SHERRY

sherry wine for See also:

• THIRTY

thirty days . (Strength, i in 20.) 2 . Ferrum redactum, reduced iron, a powder containing at least 75 % of metallic iron and a variable amount of oxide .

A preparation of it is Trochiscus ferri redacti (strength, i See also:

• GRAIN (derived through the French from Lat. granum, seed, from an Aryan root meaning " to wear down," which also appears in the common Teutonic word " corn ")

grain of reduced iron in each) . 3 . Ferri sulphas, ferrous sulphate, from which is prepared Mistura ferri composita, " Griffiths' mixture," containing ferrous sulphate 25 gr., potassium carbonate 30 gr., See also:

• MYRRH (from the Latinized form myrrha of Gr. µuppa; the Arabic murr, bitter, was applied to the substance from its bitterness)

myrrh 6o gr., See also:

• SUGAR

sugar 6o gr., spirit of See also:

• NUTMEG (from " nut," and O. Fr. mugue, musk, Lat. muscus)

nutmeg 50 m., See also:

• ROSE
• ROSE (Rosa)
• ROSE, GEORGE (1744-1818)
• ROSE, HUGH JAMES (1795—1838)
• ROSE, WILLIAM STEWART (1775-1843)

rose water 10 fl. oz . 4 . Ferri sulphas exsiccatus, which has two subpreparations: (a) Pilula ferri, " Blaud's pill " (exsiccated ferrous sulphate 15o, exsiccated sodium carbonate 95, See also:

• GUM (Fr. gomme, Lat. gommi, Gr. Kµµ1, possibly a Coptic word; distinguish " gum," the fleshy covering of the base of a tooth, in O. Eng. gbma, palate, cf. Ger. Gaumen, roof of the mouth; the ultimate origin is probably the root gha, to open wide, seen in

gum See also:

• ACACIA

acacia 5o, tragacanth 15, See also:

• GLYCERIN, GLYCERINE

glycerin to, See also:

• SYRUP (0. Fr. ysserop, mod. sirop, Span. xarope, for axarope, Arab. al, the, and sharab, drink; cf. Sherbet " and " Shrub ")

syrup 150, water 20, each to contain about I grain of ferrous carbonate); (b) Pilula aloes et ferri (Barbadoes aloes 2, exsiccated ferrous sulphate 1, compound powder of See also:

• CINNAMON

cinnamon 3, syrup of See also:

• GLUCOSE (from Gr. - twais, sweet)

glucose 3) . 5 . Ferri carbonas saccharatus, saccharated iron carbonate . The carbonate forms about one-third and is mixed with sugar into a greyish powder . 6 . Ferri arsenas, iron arsenate, ferrous and ferric arsenates with some iron oxides, a greenish powder . 7 . Ferri phosphas, a See also:

• SLATE (properly CLAY SLATE; in M. Eng. slat or sclat, from O. Fr. esclat, a small piece of wood used as a tile; esclater, to break into pieces, whence modern Fr. eclat, the root being seen also in Ger. schleissen, to split)

slate-blue powder of ferrous and ferric phosphates with some oxide .

Its preparations are: (a) Syrupus ferri phosphatis (strength, 1 gr. of ferrous phosphate in each fluid drachm) ; (b) Syrupus ferri phosphatis cum quinines et strychnina, " See also:

• EASTON

Easton's syrup " (iron wire 75 grs., concentrated phosphoric acid to A. dr., powdered See also:

• STRYCHNINE

strychnine 5 gr., See also:

• QUININE

quinine sulphate 130 gr., syrup 14 fl. oz., water to make 20 fl. oz.), in which each fluid drachm represents t gr. of ferrous phosphate, t gr. of quinine sulphate, and 22 gr. of strychnine . 8 . Syrupus ferri iodidi, iron wire, See also:

• IODINE (symbol I, atomic weight '26.92)

iodine, water and syrup (strength, 5.5 gr. of ferrous iodide in one fl. dr.) . 9 . Liquor ferri perchloridi fortis, strong solution of ferric chloride (strength, 22.5 % of iron) ; its preparations only are prescribed, viz . Liquor ferri perchloridi and Tinctura ferri perchloridi . to . Liquor ferri persulphatis, solution of ferric sulphate . i 1 . Liquor ferri pernitratus,- solution of ferric nitrate (strength, 3.3% of iron) . 12 . Liquor ferri acelatis, solution of ferric acetate .

13 . The See also:

• SCALE
• SCALE (1) A

scale preparations of iron, so called because they are dried to form scales, are three in number, the See also:

• BASE

base of all being ferric hydrate: (a) Ferrum tartaratum, dark red scales, soluble in water . (b) Ferri etq_uininae citratis, greenish yellow scales soluble in water . (c) Ferri et ammonii citratis, red scales soluble in water,. from which is prepared Vinum ferri citratis (ferri et ammonii ctratis t gr., orange wine i fl. dr.) . Substances containing tannic or gallic id turn black when See also:

• COIN
• COIN (older forms of the word are coyne, quoin and coign, all derived through the O. Fr. coing, and cuigne from Lat. cuneus, a wedge)

coin-pounded with a ferric salt, so it cannWbe used in combination with See also:

• VEGETABLE

vegetable astringents except with the infusion of See also:

• QUASSIA

quassia or calumba . Iron may, however, be prescribed in combination with See also:

• DIGITALIS

digitalis by the addition of dilute phosphoric acid . Alkalis and their carbonates, lime water, carbonate of calcium, See also:

• MAGNESIA

magnesia and its carbonate give green precipitates with ferrous and brown with ferric salts . Unofficial preparations of iron are numberless, and some of them are very useful . Ferri hydroxidum (U.S.P.), the hydrated oxide of iron, made by precipitating ferric sulphate with ammonia, is used solely as an antidote in arsenical poisoning . The Syrupus ferri phosphatis Co. is well known as " Parrish's syrup or chemical See also:

• FOOD
• FOOD (like the verb " to feed," from a Teutonic root, whence O. Eng. foda; cf. " fodder "; connected with Gr. lrareicOae, to feed)

food, and the Pilulae ferri phosphatis cum quinina et strychnina, known as Easton's pills, form a solid equivalent to Easton's syrup . There are numerous organic preparations of iron . Ferranti is a reddish brown substance which claims to be identical with the iron substance found in See also:

• PIG
• PIG (a word of obscure origin, connected with the Low Ger. and Dut. word of the same meaning, bigge)

pig's See also:

• LIVER (O. Eng. lifer; cf. cognate forms, Dutch lever, Ger. Leber, Swed. lefver, &c.; the O. H. Ger. forms are libara, lipora, &c.; the Teut. word has been connected with Gr. i'prap and Lat. jecur)

liver .

Carniferrin is another tasteless powder containing iron in combination with the phosphocarnic acid of muscle preparations, and contains 35% of iron . Ferratogen is prepared from ferric nuclein . Triferrin is a paranucleinate of iron, and contains 220/0 of iron and 210/e of organically combined phosphorus, prepared from the casein of cows See also:

• MILK (0. Eng. meoluc; from a common Indo-European root, cf. Lat. mulgere, Gr. ?t dXyetv)

milk . Haemoglobin is extracted from the blood of an ox and may be administered in bolus form . Dieterich's solution of peptonated iron contains about 2 gr. of iron per oz . Vachetta has used the albuminate of iron with striking success in See also:

• GRAVE

grave cases of See also:

• ANAEMIA (from Gr. ay-, privative, and aiµa, blood)

anaemia . Succinate of iron has been prepared by See also:

• HAUSMANN, JOHANN FRIEDRICH LUDWIG (1782-1859)

Hausmann . Ilaematogen, introduced by Hommel,. claims to contain the albuminous constituents of the blood serum and all the blood salts as well as pure haemoglobin . Sicco, the name given to dry haematogen, is a tasteless powder . Haemalbumen, introduced by Dahmen, is soluble in warm water . See also:

• THERAPEUTICS (Gr. BepaaeuTLKIi, Sc. TEXVrt, from Beparebsty, to serve)

Therapeutics . Iron is a metal which is used both as a food and as a medicine and has also a definite See also:

• LOCAL

local action .

Externally, it is not absorbed by the unbroken skin, but when applied to the broken skin, sores, ulcers and mucous surfaces, the ferric salts are powerful astringents, because they coagulate the albuminous fluids in the tissues themselves . The salts of iron quickly cause coagulation of the blood, and the See also:

• CLOT, ANTOINE

clot plugs the bleeding vessels . They thus See also:

• ACT (Lat. actus, actum)

act locally as haemostatics or styptics, and will often See also:

• ARREST (Fr. arrester, arreeter, to stop or stay)

arrest severe See also:

• HAEMORRHAGE (Gr. atµa, blood, and prryvvvac, to burst)

haemorrhage from parts which are accessible, such as the See also:

• NOSE (O.Eng. nosu, cf. Dutch neus, Swed. nos, snout; the Aix in Provence. Both at Aix and at Lyons he acquired great connexion with O.Eng. nasu is obscure, cf. Ger. Nase, Lat. pares, distinction by his labours during outbreaks of the plague. In nostrils,

nose . They were formerly used in the treatment of See also:

• POST

post partum haemorrhage . The perchloride, sulphate and pernitrate are strongly astringent; less extensively they are used in chronic discharges from the vagina, rectum and nose, while injected into the ;ectum they destroy See also:

• WORMS

worms . Internally, a large proportion of the various articles of ordinary See also:

• DIET

diet contains iron . When given medicinally preparations of iron have an astringent See also:

• TASTE (from Lat. taxare, to touch sharply; tangere, to touch)

taste, and the See also:

• TEETH (O.E. Eel); plural of tooth, O.E. top)

teeth and See also:

• TONGUE (O. Eng. lunge)

tongue are blackened owing to the formation of sulphide of iron . It is therefore advisable to take liquid iron preparations through a See also:

• GLASS
• GLASS (O.E. glees, cf. Ger. Glas, perhaps derived from an old Teutonic root gla-, a variant of glo-, having the general sense of shining, cf. " glare," " glow ")
• GLASS, STAINED

glass See also:

• TUBE (Lat. tuba)

tube or a See also:

• QUILL

quill . In the See also:

• STOMACH (Gr. vrbsaxos from arbga, a mouth)

stomach all salts of iron, whatever their nature, are converted into ferric chloride . If iron be given in excess, or if the hydrochloric acid in the gastric juice be deficient, iron acts directly as an astringent upon the mucous membrane of the stomach See also:

• WALL (O. Eng. weal, weall, Mid. Eng. wal, wane, adapted from Lat. vallum, rampart; the original O. Eng. word for a wall was wag or tenth)
• WALL, RICHARD (1694-1778)

wall . Iron, therefore, may disorder the digestion even in healthy subjects . Acid preparations are more likely to do this, and the acid set free after the formation of the chloride may act as an irritant .

Iron, therefore, must not be given to subjects in whom the gastric functions are disturbed, and it should always be given after meals . Preparations which are not acid, or are only slightly acid, such as reduced iron, dialysed iron, the carbonate and scale preparations, do not disturb the digestion . If the sulphate is prescribed in the form of a pill, it may be so coated as only to be soluble in the intestinal See also:

• DIGESTIVE

digestive fluid . In the See also:

• INTESTINE (Lat. intestinus, internal, usually in neuter plural intestina. from intus, within)

intesti