METALLOGRAPHY  .—The examination of metals and See also:

• ALLOYS (through the Fr. aloyer, from Lat. alligare, to combine)

alloys by the aid of the See also:

• MICROSCOPE (Gr. µucp6s, small, asenreiv, to %view)

microscope has assumed much importance in comparatively See also:

• RECENT

recent years, and it might at first be considered to be a natural development of the use of the microscope in determining the constitution of rocks, a study to which the name petrography has been given . It would appear, however, that it is an See also:

• EXTENSION (Lat. ex, out ; tendere, to stretch)

extension of the study of the structure of meteoric irons . There can be no question that in the See also:

• MAIN (from the Aryan root which appears in " may " and " might," and Lat. magnus, great)
• MAIN (Lat. Moenus)

main it was originated by Dr H . C . Sorby, who in 1864 gave the See also:

• BRITISH

British Association an See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

account of his See also:

• WORK

work . Following the work of Sorby came that of See also:

• PROFESSOR (the Latin noun formed from the verb profiteri, to declare publicly, to acknowledge, profess)

Professor A . See also:

• MAR, EARLDOM OF
• MAR, JOHN ERSKINE, 1ST OR 6TH EARL OF (d. 1572)
• MAR, JOHN ERSKINE, 2ND OR 7TH EARL
• MAR, JOHN ERSKINE, 6TH OR 11TH EARL OF (1675-1732)

Mar!ens of See also:

• CHARLOTTENBURG

Charlottenburg, presenting many features of originality . F . Osmond has obtained results in connexion with See also:

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

iron and See also:

• STEEL, FLORA ANNIE (1847– )

steel which are of the highest See also:

• INTEREST

interest . A See also:

• LIST (O.E. lisle, a Teutonic word, cf. Dut. lust, Ger. Leiste, adapted in Ital. lista and Fr. lisle)
• LIST, FRIEDRICH (1789-1846)

list of the more important papers by these and other workers will be found in the appended bibliography . Preparation of the Specimen.—Experience alone can enable the operator to determine what portion of a See also:

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

mass of 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 or alloy will afford a trustworthy See also:

• SAMPLE (through the O. Fr. essemple, from Lat. exemplum; a doublet of " example ")

sample of the whole . In studying a See also:

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

series of binary alloys it has been found advantageous in certain cases to obtain one See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section which will show in a See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general way the variation in structure from one end of the series to the other .

This has been effected by pouring the lighter constituent carefully on the See also:

• SURFACE

surface of the heavier constituent, and allowing solidification to take See also:

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

place . •A section through the culot so obtained will show a gradation in structure from pure metal on one See also:

• SIDE
• SIDE (mod. Eski Adalia)

side to pure metal on the other . A thin slice of metal is usually cut by means of a hack-saw driven by mechanism . The thickness of the piece should not be less than 4 in. and in See also:

• ORDER
• ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
• ORDER, HOLY

order that it may be firmly held between the fingers it should not be less than 1 in. square . The preliminary stages of polishing are effected by See also:

• EMERY (Ger. Smirgel)

emery See also:

• PAPER
• PAPER (Fr. papier, from Lat. papyrus)

paper placed preferably on wooden disks capable of being revolved at a high See also:

• RATE

rate of See also:

• SPEED, JOHN (1552–1629)

speed . The finest grade of emery paper that can be obtained is used towards the end of the operation . Before use the finer papers should be rubbed with a hard steel surface to remove any coarse particles . The completion of the operation of polishing is generally effected on wet See also:

• CLOTH

cloth or See also:

• PARCHMENT

parchment covered with a small amount of carefully washed jeweller's See also:

• ROUGE (" red," from Lat. rubeus)

rouge . Various See also:

• MECHANICAL

mechanical appliances are employed to minimize the labour and 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 required for the polishing . These usually consist of a series of interchangeable revolving disks, each of which is covered with emery paper, cloth or parchment, according to the particular See also:

• STAGE (Fr. 6/age; from Lat. stare, to stand)

stage of polishing for which it is required . In the See also:

• CASE
• CASE, JOHN (d. 1600)

case of brittle alloys and of alloys having a very soft constituent, which during polishing tends to spread over and obliterate the harder constituents, polishing is in many cases altogether avoided by casting the alloy on the surface of 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 or See also:

• MICA

mica . In this way, with a little care, a perfect surface is obtained, and it is only necessary to develop the structure by suitable See also:

• ETCHING (Dutch, etsen, to eat)

etching .

In adopting this method, however, instances have occurred in which the removal of the 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 surface has shown a structure differing considerably from the See also:

• ORIGINAL

original . Polishing in Bas-See also:

• RELIEF

Relief.—If the polishing be completed with See also:

• FINE

fine rouge on a See also:

• SHEET

sheet of wet parchment, placed upon a comparatively soft bas such as a piece of See also:

• DEAL

deal, certain soft constituents of an alloy may often be eroded in such a manner as to leave the hardest portions in relief . For the later stages of polishing H . L . Le Chatelier recommends the use of alumina obtained by the calcination of ammonium See also:

• ALUM

alum; and for the final See also:

• POLISH

polish of soft metals, See also:

• CHROMIUM (symbol Cr. atomic weight 52.1)

chromium See also:

• OXIDE

oxide . Although in some cases a See also:

• PATTERN

pattern becomes visible after polishing, yet more frequently a See also:

• MIRROR (through O. Fr. mirour, mod. miroir, from a sup-posed Late Lat. miratorium, from mirari, to admire)

mirror-like surface is produced in which no pattern can be detected, or if there is a pattern it is blurred, as if seen through a See also:

• VEIL (O.Fr. veile, mod. voile, from Lat. velum, cloth, awning, sail)

veil or mist . This is due to a thin layer of metal which has been dragged, or smeared, uniformly over the whole surface by the See also:

• FRICTION (from Lat. fricare, to rub)

friction of the polishing See also:

• PROCESS

process . Such a surface layer is formed in all cases of polishing, and the See also:

• PECULIAR

peculiar lustre of burnished See also:

• SILVER

silver or steel is probably due to this layer . But to the metallographist it is an inconvenience, as it conceals scratches See also:

• LEFT

left by imperfect polishing, and also hides the pattern . It is therefore desirable to conduct the polishing so as to make this layer as thin as possible: it is claimed for alumina that it can be so used as to produce a much thinner surface layer than that due to the employment of rouge . The surface layer is very readily removed by appropriate liquid reagents, and, the true surface of the metal having been laid See also:

• BARE

bare, the etching reagent acts differently on the individual substances in the alloy and the pattern can thus be emphasized to any required extent . Osmond divides etching reagents into three classes—acids, See also:

• HALOGENS

halogens and salts .

As regards acids, See also:

• WATER

water containing from z to ro% of hydrochromic See also:

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

acid is useful . It is made by mixing to grams of See also:

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

potassium bichromate with ro grams of sulphuric acid in roo grams of water . The use of nitric acid requires much experience . It is frequently employed in the examination of steels, See also:

• SIR

Sir W . C . See also:

• ROBERTS, DAVID (1796-1864)
• ROBERTS, FREDERICK SLEIGH ROBERTS, EARL

Roberts-See also:

• AUSTEN, JANE (1775-1817)

Austen preferred a 1% See also:

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

solution in See also:

• ALCOHOL

alcohol, but many workers use concentrated acid, and effect the etching by allowing a stream of water to dilute the film of acid left on the surface of the specimen after dipping it . Of the halogens, See also:

• IODINE (symbol I, atomic weight '26.92)

iodine is the most useful . A solution in alcohol is applied, so that a single drop covers See also:

• HALF

half a square See also:

• INCH (O. Eng. ynce from Lat. uncia, a twelfthpart; cf. " ounce," and see As)

inch of surface . The specimen is then washed with alcohol, and dried with a piece of fine See also:

• LINEN

linen or See also:

• CHAMOIS

chamois See also:

• LEATHER (a word which appears in all Teutonic languages; cf. Ger. Leder, Dutch leer or leder, Swed. leder, and in such Celtic forms as Welsh llader)
• LEATHER, ARTIFICIAL

leather . See also:

• TINCTURE (Fr. teinture, Lat. tinctura, tingere, to dye, stain)

Tincture of iodine also affords a means of identifying See also:

• LEAD
• LEAD (pronounced iced)

lead in certain alloys by the formation of a yellow iodide of lead, while the vapour of iodine has in certain cases been used to tint the constituents . Thin coloured films may often be produced by the oxidation of the specimen when heated in See also:

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

air . This, as a means of developing the structure, in the case of the See also:

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

copper alloys is specially useful .

Tinted crystals may thus be distinguished from the investing layer caused by the presence of a See also:

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

minute quantity of another constituent . The See also:

• TEMPER (from Lat. temperare, to mingle or compound in due proportion, to qualify, rule, regulate, to be moderate, formed from tempos, time, fit or due season)

temper See also:

• COLOURS, MILITARY

colours produced by See also:

• HEATING

heating iron or steel in air are well known . See also:

• CARBIDE

Carbide of iron is less oxidizable than the iron with which it is intimately associated, and it assumes a 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 tint, while the iron has reached the See also:

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

blue stage . These coloured films may be fixed by covering with thin films of gelatine . In some cases the alloy may be attacked electrolytically by exposing it for a few minutes to a weak electric current in a See also:

• BATH
• BATH, THOMAS THYNNE
• BATH, WILLIAM

bath of very dilute sulphuric acid . Certain organic bodies give very satisfactory results . The See also:

• JAPANESE

Japanese, for instance, produce most remarkable effects by See also:

• SIMPLE

simple reagents of which an infusion of certain forms of grass is a not unimportant constituent . In the case of iron and steel a freshly prepared infusion of See also:

• LIQUORICE

liquorice See also:

• ROOT (late O.E. rot, adopted from Scand., cf. Norw. and Swed. rot, Dan. rod; the true O.E. word was wyrt, plant, represented in Ger. Wurz or Wurzel; the ultimate root is the same in both words, and is seen in Lat. radix)
• ROOT, ELIHU (1845– )

root has been found to be most useful for colouring certain constituents of steel . Osmond, who was the first to use this reagent, insisted that it should be freshly prepared and always used under identical conditions as regards See also:

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

age and concentration . His method of applying it was to rub the specimen on parchment moistened with it, but he has subsequently modified this " polish attack " by substituting a 2% solution of ammonium nitrate for the liquorice infusion . In each case a small quantity of freshly precipitated See also:

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

calcium sulphate is used on the parchment to assist the polishing . Appliances used in Micrography.—The method of using the microscope in connexion with a See also:

• CAMERA (a Latin adaptation of Gr. Kagapa, an arched chamber)

camera for photographic purposes will now be considered .

Every micrographer has his own views as should be an achromatic one, as See also:

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

colour effects cause trouble in photographing the See also:

• OBJECTS

objects . For See also:

• LOWER

lower See also:

• POWERS, HIRAM (1805-1873)

powers the Lieberkuhn parabolic illuminator is useful . Certain See also:

• GROUPS
• GROUPS, THEORY

groups of alloys show better under oblique See also:

• ILLUMINATION

illumination, which may be effected by the aid of a See also:

• GOOD, JOHN MASON (1764-1827)

good condensing See also:

• LENS
• LENS (from Lat. lens, lentil, on account of the similarity of the form of a lens to that of a lentil seed)

lens, the See also:

• ANGLE (from the Lat. angulus, a corner, a diminutive, of which the primitive form, angus, does not occur in Latin; cognate are the Lat. angere, to compress into a bend or to strangle, and the Gr. ayKOS, a bend; both connected with the Aryan root ank-, to

angle of incidence being limited by the distance of the See also:

• OBJECT

object from the See also:

• OBJECTIVE, or OBJECT GLASS

objective in the case of high magnification . As regards objectives, the most useful are the Zeiss 2 mm., 4 mm. and 24 mm.; two other useful objectives for See also:

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

low powers being 35 mm. and 70 mm., both of which are projecting objectives . A projecting See also:

• EYE
• EYE (O. Eng. edge, Ger. Auge; derived from an Indo-European root also seen in Lat. oc-ulus, the organ of vision (q.v.)

eye-piece, prefer-ably of low See also:

• POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power, should be employed with all but the two latter objectives . The See also:

• IMMERSION (Lat. immersio, dipping),

immersion lens, the Zeiss 2 mm., is used with specially thickened See also:

• CEDAR (Lat. cedrus, Gr. iapos)

cedar oil, and if the distance from the objective to the See also:

• PLATE

plate is 7 feet, magnifications of over 2000 diameters can easily be obtained . As regards sensitized plates, excellent results have been obtained with Lumiere plates sensitive to yellow and 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 The various brands of " process " plates are very serviceable where the contrasts on the specimen are not See also:

• GREAT

great . Some reproductions of photo-micrographs of metals and alloys will be found in the plate accompanying the See also:

• ARTICLE (from Lat. articulus, a joint)

article ALLOYS . W . C . Roberts-Austen and F . Osmond, " On the Structure of Metals, its Origin and Causes," Phil .

Trans . See also:

• ROY, WILLIAM (1726-1790)

Roy . See also:

• SOC

Soc. clxxxvii . 417—4.32; and See also:

• BULL
• BULL, GEORGE (1634–1710)
• BULL, JOHN (c. 1562–1628)
• BULL, OLE BORNEMANN (18ro-188o)

Bull. de la Soc. d'encouragement pour l'industrie nationale, 5e eerie, i . 1136 (Aoflt 1896) ; G . Charpy, " Micro- Micrographic Apparatus. scopic Study of Me- tallic Alloys," Bull . to the See also:

• FORM (Lat. forma)

form of an See also:

• INSTALLATION

installation to be adopted, and it will therefore I de la sec. d'encouragement pour l'industrie nationale (See also:

• MARCH
• MARCH (1) (from Fr. marcher, to walk; the earliest sense in French appears to be " to trample," and the origin has usually been found in the Lat. marcus, hammer; Low Lat. marcare, to hammer; hence to beat the road with the regular tread of a soldier: cf.
• MARCH, AUZIAS (c. "1395-1458)
• MARCH, EARLS OF
• MARCH, FRANCIS ANDREW (1825– )

March, 1897) ; A. be well to give an See also:

• ILLUSTRATION

illustration of a definite apparatus which has Sauveur, Constitution of Steel," Technology Quarterly (See also:

• JUNE

June, 1888) ; been found to give satisfactory results . It consists of a micro- See also:

• SCOPE (through Ital. scopo, aim, purpose, intent, from Gr. o'KOaos, mark to shoot at, aim, o ic07reiv, to see, whence the termination in telescope, microscope, &c.)

scope A with a See also:

• FIRM

firm See also:

• BASE

base placed in a See also:

• HORIZONTAL

horizontal position . The microscope can be connected by a See also:

• TUBE (Lat. tuba)

tube; B with the See also:

• EXPANDED

expanded camera CC, at the end of which .is the usual See also:

• FRAME

frame to receive the «Crystalline Structure of Metals," Phil . Trans . Roy . Soc. cxciii. photographic plate .

A practised observer can See also:

• FOCUS (Latin for " hearth " or " fireplace ")

focus on a plate 1353 and cxcv . 279; F . Osmond, " See also:

• CRYSTALLOGRAPHY
• CRYSTALLOGRAPHY (from the Gr. Kpbo TaXXO , ice, and -ypachew, to write)

Crystallography of Iron," Annales of clear glass by the aid of a subsidiary low-power microscope See also:

• DES

des Mines (See also:

• JANUARY

January ,9o0) ; Le Chatelier, Technology of Metallolens . If a semi-transparent plate is employed it should be as fine graphs," Metallogr¢phist, vol. iv . No . 1; Contribution a l'etude des as possible . The surface of the table is cut in such a way near H alliages . Societe d'encour¢gement pour l'industrie nationale (1901); See also:

• SMEATON, JOHN (1724–1792)

Smeaton, " Notes on the Etching of Steel Sections," Iron and Steel that the observer who is seated may conveniently examine the See also:

• MAGAZINE

Magazine, vol. ix . No . 3 . (W . C .

R.-A.; F . H . NE.) object on the stage of the microscope, the portion B turning METALLURGY, the See also:

• ART

art of extracting metals from their ores; aside for this purpose . The subsequent focusing is effected by a the See also:

• TERM

term being customarily restricted to commercial as opposed See also:

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

rod, FFF, and gearing attached to the fine See also:

• ADJUSTMENT (from late Lat. ad juxtare, derived from juxta, near, but early confounded with a supposed derivation from justus, right)

adjustment of the to laboratory methods . It is convenient to treat See also:

• ELECTRICAL
• ELECTRICAL (or ELECTROSTATIC) MACHINE

electrical processes of extraction as forming the subjects of See also:

• ELECTROCHEMISTRY

Electrochemistry and See also:

• ELECTROMETALLURGY

Electrometallurgy (qq.v.) . The following table enumerates in the order of their importance the metals which,our subject at See also:

• PRESENT

present is understood to include; the second See also:

• COLUMN (Lat. columna)

column gives the chemical characters of the ores utilized, italics indicating those of subordinate importance . The term " oxide " includes carbonate, See also:

• HYDRATE

hydrate, and, when marked with*, silicate . Metal . See also:

• CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

Character of Ores . Iron Oxides, sulphide . Copper Complex sulphides, also oxides, metal . Silver Sulphide and reguline metal, chloride .

See also:

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

Gold Reguline metal . Lead Sulphide and basic carbonate, sulphate, &c . See also:

• ZINC

Zinc Sulphide, oxide.* See also:

• TIN (Lat.- stannum, whence the chemical symbol " Sn "; atomic weight =117.6, 0=16)

Tin Oxide . Metallographist, vol. i . No . 3; " Metallography applied to Foundry Work," The Iron and Steel Magazine, vol. ix . No . 6, and vol. x . No . 1; J . E . See also:

• STEAD, WILLIAM THOMAS (1849– )

Stead, " Crystalline Structure of Iron and Steel," Journ .

Iron and Steel Inst . (1898), i . 145; " See also:

• PRACTICAL

Practical Metallography," Prot . See also:

• CLEVELAND
• CLEVELAND (or CLEIVELAND), JOHN (1613—1658)
• CLEVELAND, BARBARA VILLIERS, DUCHESS OF (1641-1709)
• CLEVELAND, STEPHEN GROVER (1837-1908)

Cleveland Inst. of See also:

• ENGINEERS, MILITARY

Engineers (Feb . 26, 1900) ; See also:

• EWING
• EWING, ALEXANDER (1814-1873)
• EWING, THOMAS (1789-1871)

Ewing and Rosenhain, microscope, GA; flap J when raised forms the support of the See also:

• LAMP (from Gr. Xag ras, a torch, Xaµaav, to shine)

lamp used for illumination . As an illuminant an arc See also:

• LIGHT

light has many advantages, as the exposure of the plate used will seldom exceed to seconds . The filament of a Nernst lamp can be used as the source of light; though not so brilliant as the arc it possesses the great See also:

• ADVANTAGE

advantage of perfect immobility . For the best results, especially with high powers, the source of light must be small, so that its See also:

• IMAGE (Lat. imago, perhaps from the same root as imitari, copy, imitate)

image can be focussed on to the surface of the object; this advantage is possessed by both of these illuminants . Next in value comes the See also:

• ACETYLENE

acetylene See also:

• FLAME (Lat. flamma; the root flag- appears in flagrare, to burn, blaze, and Gr. d, XEryew)

flame, and an incandescent lamp or a See also:

• GAS

gas lamp with a See also:

• MANTLE

mantle will give good results, but with much longer exposure . Actual illumination is best effected by a See also:

• BECK (or BEEK), DAVID (1621—1656)
• BECK, CHRISTIAN DANIEL (1757-1832)
• BECK, JAKOB SIGISMUND (1761-1840)

Beck See also:

• VERTICAL (from Lat. vertex, highest point)

vertical illuminator or a Zeiss See also:

• PRISM (Gr. rrpivµa, properly a thing sawn, Irpii"ety, to saw)

prism . It is necessary that the lens used for concentrating the light on the illuminator General Sequence of Operations.—Occasionally, but rarely, Sulphides.—Iron, copper, lead, zinc, See also:

• MERCURY
• MERCURY (MERCU1uus)
• MERCURY (symbol Hg, atomic weight = 2oo)

mercury, silver and See also:

• ANTIMONY (symbol Sb, atomic weight 120.2)

antimony very frequently present themselves in this See also:

• STATE
• STATE, GREAT OFFICERS OF

state of See also:

• COMBINATION (Lat. combinare, to combine)

combination, as metallic ores occur as practically pure compact masses, from components of a See also:

• FAMILY

family of ores which may be divided into two which the accompanying See also:

• MATRIX

matrix or " See also:

• GANGUE, or CANG

gangue " can be detached sections: (L)' such as substantially consist of simple sulphides, as by See also:

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

hand and See also:

• HAMMER, FRIEDRICH JULIUS (1810-1862)

hammer . In most cases the " ore " (see See also:

• MINERAL

MINERAL, iron See also:

• PYRITES

pyrites (FeS2), See also:

• GALENA

galena (See also:

• PBS

PbS), zinc See also:

• BLENDE, or SPHALERITE

blende (ZnS), See also:

• CINNABAR (Ger. Zinnober)

cinnabar (HgS) ; DEPOSITS; See also:

• VEINS

VEINS), as it comes out of the mine or See also:

• QUARRY

quarry, is and (2) complex sulphides, such as the various kinds of sulphureous simply mixture of ore and in which the latter copper ores (all substantially compounds or mixtures of sulphides a m proper gangue, of copper and iron) ; See also:

• BOURNONITE

bournonite, a complex sulphide of lead, See also:

• ANTI, or CAMPA

anti-not unfrequently predominates .

Hence it is generally necessary mony and copper; rothgiltigerz, sulphide of silver, antimony, and to purify the ore before the liberation of the metal is attempted. See also:

• ARSENIC (symbol As, atomic weight 75.0)

arsenic; fahlerz, sulphides of arsenic and antimony, combined with Most metallic ores are specifically heavier than the accompanying sulth ide es of and otherrsul ver, i wi, zinone c, another' silver; and mixtures impurities and their See also:

• PURIFICATION

purification is generally effected by reducing In treating a sulphureous ore, the first step as a See also:

• RULE

rule is to subject the crude ore to a fine enough See also:

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

powder to detach the metallic it to oxidation by roasting it in a reverberatory or other See also:

• FURNACE

furnace, from the earthy See also:

• PART

part, and then washing away the latter by a which leads to the burning away of at least part of the arsenic and current of water, as far as possible (see ORE-DRESSING). part of the See also:

• SULPHUR

sulphur . The effect on the several individual metallic The See also:

• MAJORITY (Fr. majorite; Med. Lat. majoritas; Lat. major, greater)

majority of ores being chemical compounds, the extraction sulphides (supposing only one of these to be present) is as follows: — g L . Those of silver (Ag2S) and mercury (HgS) yield sulphur dioxide of their metals demands chemical treatment . The chemical gas and metal; in the case of silver, sulphate is formed at low See also:

• TERN (Norsk taerne, tende or tende; Swedish tarna; Dutch Stern1)

tern- operations involved may be classified as follows:— peratures . Metallic mercury, in the circumstances, goes off as a 1 . Fiery Operations.—The ore, generally with some " See also:

• FLUX (Lat. fluxus, a flowing; this being also the meaning of the English term in medicine, &c.)

flux," vapour, which is collected and condensed; silver -remains as a See also:

• REGULUS, MARCUS ATILIUS

regulus, is exposed to the See also:

• ACTION

action of See also:

• FIRE (in O. Eng. f j'r; the word is common to West German languages, cf. Dutch vuur, Ger. Feuer; the pre-Teutonic form is seen in Sanskrit pu, pavaka, and Gr. irup; the ultimate origin is usually taken to be a root meaning to purify, cf. Lat. purus)

fire . The fire in most cases has a but pure sulphide of silver is hardly ever worked . 2 . Sulphides of iron and zinc yield the oxides Fe20a and ZnO as chemical, in addition to its See also:

• PHYSICAL

physical, See also:

• FUNCTION

function . Moreover the final products, some basic sulphate being formed at the earlier stages, furnace (q.v.) is designed so as to facilitate the action of the 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 especially in the case of zinc . The oxides can be reduced by See also:

• CARBON (symbol C, atomic weight 12)

carbon. and furnace gases in the desired direction . It is intended either 3 .

The sulphides of lead and copper yield, the former a mixture to See also:

• BURN, RICHARD (1709-1785)

burn away certain components of the ore—in which case it of oxide and normal sulphate, the latter one of oxide and basic sulphate . Sulphate of lead is See also:

• STABLE

stable at a red heat; sulphate of copper must be so regulated as to contain a sufficient excess of unburned breaks up into oxide, sulphur dioxide and See also:

• OXYGEN (symbol 0, atomic weight 16)

oxygen . In practice, oxygen; or it is meant to deoxidize (" reduce ") the ore,when the neither oxidation process is ever pushed to the end; it is stopped See also:

• DRAUGHT (from the common Teutonic word " to draw "; cf. Ger. 7'racht, load; the pronunciation led to the variant form " draft," now confined to certain specific meanings)

draught must be restricted so as to keep the ore constantly as soon as the mixture of roasting-product and unchanged sulphide d up in combustible flame gases (carbon monoxide, contains oxygen and sulphur in the ratio of 02 : S . The See also:

• ACCESS (Lat. accessus)

access of wrapped is then stopped and the whole heated to a higher temperature, See also:

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

hydrogen, See also:

• MARSH (O. F. mersc, for merisc, a place full of "meres" or pools; cf. Ger. Meer, sea, Lat. mare)
• MARSH, ADAM (ADAM DE MARISCO) (d. c. 1258)
• MARSH, GEORGE PERKINS (1801-1882)
• MARSH, HERBERT (1757–1839)
• MARSH, NARCISSUS (1638-1713)
• MARSH, OTHNIEL CHARLES (1831-1899)

marsh-gas, &c.) . The majority of the chemical when the whole of the sulphur and oxygen is eliminated . This operations of metallurgy fall into this See also:

• CATEGORY (Gr. Karrlyopia, " accusation ")

category, and in these method is largely utilized in the smelting of lead from galena and of processes other metal-reducing agents than those naturally copper from copper pyrites . contained in the fire (or blast) are only exceptionally employed . 4 . Sulphide of antimony, when roasted in air, is converted into a See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind of alloy of sulphide and oxide; the same holds for iron, only 2 . Amalgamation.—The ore by itself (if it is a reguline one), its oxysulphide is quite readily converted into the pure oxide . Fe2Oa or with certain reagents (if it is not), is worked up with mercury by further roasting . Oxysulphide of antimony, by suitable processes so that the metal is obtained as an See also:

• AMALGAM

amalgam, which can be separ- can be reduced to metal, but these processes are rarely used, because ated mechanically from the dross .

The purified amalgam is the same end is far more easily obtained by " precipitation," i.e . withdrawing the sulphur by See also:

• FUSION

fusion with metallic iron, forming distilled, when the mercury is recovered as a distillate while the metallic antimony and sulphide of iron . Both products fuse, but metal remains. readily part, because fused antimony is far heavier than fused 3 . Wet Processes.—Strictly speaking, certain amalgamation sulphide of iron . A precisely similar method is used occasionally methods fall under this See also:

• HEAD (in 0. Eng. heafad; the word is common to Teutonic languages; cf. Dutch hoofd, Ger. Haupt, generally taken to be in origin connected with Lat. caput, Gr. KerbOvi7)
• HEAD, SIR EDMUND WALKER, BART
• HEAD, SIR FRANCIS BOND, BART

head; but, in its See also:

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

ordinary See also:

• ACCEPTANCE (Lat. acceptare, frequentative form of accipere, to receive)

acceptance, the for the reduction of lead from galena . Sulphide of lead, when fused term refers to processes in which the metal is extracted either ao egulus (it= LPb) and a " See also:

• MAT (O. Eng. meatt, from late Lat. mattes, whence Ital. mallet, Ger. and Dan. matte, Du. mat, &c.)

mat " FeS which, ho ever,See also:

• ION

Ion cooling, from the natural ore, or from the ore after roasting or other decomposes into the ordinary sulphide FeS,.and finely divided iron. preliminary treatment, by an acid or 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 solution, and from this What we have been explaining are See also:

• SPECIAL

special cases of a more general solution precipitated—generally in the reguline form—by some metallurgic proposition: Any one of the metals, copper, iron, tin, zinc, lead, silver, antimony, arsenic, in general, is capable of de-suitable reagent. sulphurizing (at least partially) any of the others that follows it in Few methods of metal extraction at once yield a pure product. the series just given, and it does so the more readily and completely What as a rule is obtained is a more or less impure metal, which the greater the number of intervening terms . Hence, supposing requires to be "refined " to become See also:

• FIT

fit for the See also:

• MARKET (Lat. mercatus, trade or place of trade)

market. a See also:

• COMPLETE

complete mixture of these metals to be melted down under circum- stances admitting of only a partial sulphuration of the whole, the Chemical Operations.—Amalgamation and wet-way processes copper has the best See also:

• CHANCE (through the O. Fr. cheance, from the Late Lat. cadentia, things happening, from cadere, to fall out, happen; cf. " case ")

chance of passing into the " mat," while the have limited applications, being practically confined to copper, gold arsenic is the first to be eliminated as such, or, in the presence of and silver . We therefore here confine ourselves, in the main, to oxidants, as oxide . pyro-chemical operations . Arsenides.—Although arsenides are amongst the commonest The method to be adopted for the extraction of a metal from its impurities of ores generally, ores consisting essentially of arsenides ore is determined chiefly, though not entirely, by the nature of the are comparatively rare . The most important are certain 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 non-metallic component with which the metal is combined . The arsenides of See also:

• COBALT (symbol Co, atomic weight 59)

cobalt and See also:

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

nickel, which in practice are always See also:

• CON

con-simplest case is that of the reguline ores where there is no non- taminated with the arsenides or other compounds of See also:

• FOREIGN

foreign metals, metallic See also:

• ELEMENT (Lat. elementum)

element .

The important case is that of gold. such as iron, See also:

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

manganese, &c . The general mode of working these Oxides, Hydrates, See also:

• CARBONATES

Carbonates and Silicates.—All iron and tin ores ores is as follows . The ore is first roasted by itself, when a part of proper fall under this heading, which, besides, comprises certain ores the arsenic goes off as such and as oxide, while a complex of lower of copper, of lead and of zinc . 1'he first step consists in subjecting arsenides remains . This See also:

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

residue is now subjected to careful oxidisx, the crude ore to a roasting or calcining process, the object of which See also:

• ING

ing fusion in the presence of some solvent for metallic bases . The is to remove the water and carbon dioxide, and burn away, to some effect is that the several metals are oxidized away and pass into the extent at least, the sulphur, arsenic or organic See also:

• MATTER

matter . The residue slag (as silicates) in the following order—manganese, iron, cobalt, consists of an impure oxide of the respective metal, which in all cases nickel; and at any stage the as yet unoxidized residue of arsenide is reduced by treatment with See also:

• FUEL (O. Fr. feuaile, popular Lat. focalia, from focus, hearth, fire)

fuel at a high temperature . Should assumes the form of a fused regulus, which sinks down through. the the metal be present as a silicate, See also:

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

lime must be added in the smelting slag as a " speis." (This term has the same meaning in reference to remove the See also:

• SILICA

silica and liberate the oxide. to arsenides as " mat " has in regard to sulphides.) By stopping The temperature required for the reduction of zinc lies above the the process at the right moment, we can produce a speis which boiling point of the metal; hence the mixture of ore and reducing contains only cobalt and nickel, and if at this stage also the flux is See also:

• AGENT (from Lat. agere, to act)

agent (See also:

• CHARCOAL

charcoal is generally used) must be heated in a,See also:

• RETORT (Lat. retorquere, to twist or turn back)

retort combined renewed we can further produce a speis which contains only nickel with condensing apparatus . In all the other cases the reduction and a slag which substantially is one of cobalt only . The composiis effected in the fire itself, a See also:

• TOWER (Lat. turris; Fr. tour, clocker; Ital. torre; Ger. Thurm)

tower-shaped blast furnace being pre- tion of the speises generally varies from AsMe 812 to AsMe2, where ferably used . The furnace is charged with alternate layers of fuel " Me " means one atomic See also:

• WEIGHT

weight of metal in toto, so that in general and ore (or rather ore and flux, see below), and the whole kindled 'Me = xFe + yCo + zNi, where x + y + z = I . The siliceous Metal .

Character of Ores . Mercury . . Sulphide, reguline metal . Antimony . Sulphide . See also:

• BISMUTH

Bismuth ..... Reguline metal . Nickel and cobalt . Arsenides . See also:

• PLATINUM [symbol Pt, atomic weight 145.0 (0=16)]

Platinum, See also:

• IRIDIUM (symbol Ir.; atomic weight 193.1)

iridium, &c . . Reguline . from below .

The metallic oxide, partly by the See also:

• DIRECT

direct action of the carbon with which it is in contact, but principally by that of the carbon monoxide produced in the lower strata from the oxygen of the blast and the hot carbon there, is reduced to the metallic state; the metal fuses and runs down, with the slag, to the bottom of the furnace, whence both are withdrawn by opening plug-holes . cobalt is utilized as a blue pigment called " smalt "; the nickel-speis is worked up for metal . See also:

• MINOR
• MINOR (Lat. for smaller, lesser)
• MINOR, ROBERT CRANNELL (1839-1904)

Minor Reagents.—Besides the oxidizing and reducing agents present in the fire, and the " fluxes " added for the See also:

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

production of slags, various minor reagents may be noticed . Metallic iron as a desulphurizer has already been referred to . Oxide of lead, PbO (litharge), is largely used as an oxidizing agent . At a red heat, when it melts, it readily attacks all metals, except silver and gold, the general result being the formation of a mixed oxide and of a mixed regulus, a See also:

• DISTRIBUTION (Lat. distribuere, to deal out)

distribution, in other words, of both the lead and the metal acted on between slag and regulus . More important is its action on metallic sulphides, which, in general, results in the formation of three things besides sulphur dioxide, viz. a mixed oxide slag including the excess of litharge, a regulus of lead (which may include bismuth and other more readily reducible metals), and, if the litharge is not sufficient for a complete oxidation, a " mat " comprising the more readily sulphurizable metals . Oxide of lead, being a most powerful solvent for metallic oxides generally, is also largely used for the separation of silver or gold from base metallic oxides . Metallic lead is to metals generally what oxide of lead is to metallic oxides . It accordingly is available as a solvent for taking up small particles of metal diffused throughout a mass of slag, and uniting them into one regulus . This leads us to the process of " cupellation," which serves for the extraction of gold (q.v.; see also See also:

• ASSAYING

ASSAYING) and silver from their alloys with base metals . Fluxes.—All ores are contaminated with more or less gangue, which in general consists of infusible matter, and if left unheeded in the reduction of the metallic part of the ore would retain more or less of the metal disseminated through it, or at best foul the furnace .

To avoid this, the ore as it goes into the furnace is mixed with " fluxes " so selected as to convert the gangue into a fusible . " slag," which readily runs down through the fuel with the regulus and separates from the latter . The quality and proportion of flux should, if possible, be so chosen that the formation of the slag sets in only after the metal has been reduced and molten; or else part of the basic oxide of the metal. to be extracted may be dissolved by the slag and its reduction thus be prevented or retarded . Slags are not a necessary evil; if an ore were See also:

• FREE

free from gangue we should add gangue and flux from without to produce a slag, because one of its functions is to form a layer on the regulus which protects it against the further action of the blast or furnace gases . Fluxes may be arranged under the three heads of (I) fluor-spar, (2) basic fluxes and (3) acid fluxes . Fluor-spar fuses up at a red heat with silica, sulphates of calcium and See also:

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

barium, and a few other infusible substances into homogeneous masses . It shows little tendency to dissolve basic oxides, such as lime, &c . One part of fluor-spar liquefies about half a part of silica, four parts of calcium sulphate and one and a half parts of barium sulphate . Upon these facts its extremely wide application in metallurgy is founded . Carbonate of soda (or potash is the most powerful basic flux . It dissolves silica and all silicates into fusible glasses . On the other hand, See also:

• BORAX (sodium pyroborate or sodium biborate)

borax may be taken as a type for the acid fluxes .

At a red heat, when it forms a viscid fluid, it readily dissolves all basic oxides into fusible complex borates . Now the gangue of an ore in general consists either of some basic material such as carbonate of lime (or See also:

• MAGNESIA

magnesia), ferric oxide, alumina, &c., or of silica (See also:

• QUARTZ

quartz) or some more or less acid silicate, or else of a mixture of the two classes of bodies . So any kind of gangue might be liquefied by means of borax or by means of alkaline carbonate; but neither of the two is used otherwise than for assaying; what the metal-smelter does is to add to a .basic gangue the proportion of silica, and to an acid ore the proportion of lime, or, indirectly, of ferrous or perhaps manganous oxide, which it may need for the formation of a slag of the proper qualities . The slag must possess the proper degree of saturation . In other words, taking SiO2+ nMeO (where MeO means an See also:

• EQUIVALENT

equivalent of base) as a See also:

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

formula for the potential slag, n must have the proper value . If n is too small, i.e. if the slag is too acid, it may dissolve part of the metal to be recovered; if n is too great, i.e. the slag too basic, it may refuse to dissolve, for instance, the ferrous oxide which is meant to go into it, and this oxide will then be reduced, and its metal (iron in our example) contaminate the regulus . In reference to the problem under discussion, it is See also:

• WORTH
• WORTH, CHARLES FREDERICK (1825-1895)

worth noting that oxides of lead and copper are more readily reduced to metals than oxide of iron Fe203 is to FeO, the latter more readily to FeO than FeO itself to metal, and FeO more readily to metal than manganous oxide is . Oxide of calcium (lime) is not reducible at all . The order of basicity in the oxides (their readiness to go into the slag) is precisely the See also:

• REVERSE

reverse . Most slags being, as we have seen, complex silicates, it is a most important problem of scientific metallurgy to determine the relations in this class of bodies between chemical See also:

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

composition on the one hand and fusibility and solvent power for certain oxides (CaO, FeO, Fe2Oi, Al203, SiO2, &c.) on the other . Their general composition may be expressed as n(MO-f-xSiO2)+m[(fe or al)O +xSiO2] (M=Ca, Mg, Fe, K2, &c.; fe =Fe, al=;Al.) The following mode of classifying and naming composition in silicates is metallurgical; scientific chemists designate Class I. as orthosilicates, Class II. as metasilicates, Class III. as sesquisilicates . In the formulae M stands for K2, Ca, Fe, &c., or for al=fAl, fe=;Fe, &c .

Name . Formula . Oxygen Ratio. x I . Singulo-silicates ISiOi+IMO tease . Acid . ` 1 i . ISi0ii-IMO i 2 I II . . . Bi-silicates It should be possible to represent each quality of a silicate as a function of x, n/m, and of the nature of the individual bases that make up the MO and (fe or al) 0 respectively . Our actual knowledge falls far See also:

• SHORT, FRANCIS JOB (1857– )

short of this possibility . The problem, in fact, is very difficult, the more so as it is complicated by the existence of aluminates, compounds such as Al203 . 3CaO, in which the alumina plays the part of acid, and the occasional existence of compounds of fluorides and silicates in certain slags .

The formation of slags, or, what comes to the same thing, of metallic silicates, was especially studied by See also:

• PERCY (FAMILY)
• PERCY, SIR HENRY
• PERCY, THOMAS (1729-1811)
• PERCY, THOMAS (c. 156o-16os)

Percy, See also:

• SMITH
• SMITH, ADAM (1723–1790)
• SMITH, ALEXANDER (183o-1867)
• SMITH, ANDREW JACKSON (1815-1897)
• SMITH, CHARLES EMORY (1842–1908)
• SMITH, CHARLES FERGUSON (1807–1862)
• SMITH, CHARLOTTE (1749-1806)
• SMITH, COLVIN (1795—1875)
• SMITH, EDMUND KIRBY (1824-1893)
• SMITH, G
• SMITH, GEORGE (1789-1846)
• SMITH, GEORGE (184o-1876)
• SMITH, GEORGE ADAM (1856- )
• SMITH, GERRIT (1797–1874)
• SMITH, GOLDWIN (1823-191o)
• SMITH, HENRY BOYNTON (1815-1877)
• SMITH, HENRY JOHN STEPHEN (1826-1883)
• SMITH, HENRY PRESERVED (1847– )
• SMITH, JAMES (1775–1839)
• SMITH, JOHN (1579-1631)
• SMITH, JOHN RAPHAEL (1752–1812)
• SMITH, JOSEPH, JR
• SMITH, MORGAN LEWIS (1822–1874)
• SMITH, RICHARD BAIRD (1818-1861)
• SMITH, ROBERT (1689-1768)
• SMITH, SIR HENRY GEORGE WAKELYN
• SMITH, SIR THOMAS (1513-1577)
• SMITH, SIR WILLIAM (1813-1893)
• SMITH, SIR WILLIAM SIDNEY (1764-1840)
• SMITH, SYDNEY (1771-1845)
• SMITH, THOMAS SOUTHWOOD (1788-1861)
• SMITH, WILLIAM (1769-1839)
• SMITH, WILLIAM (c. 1730-1819)
• SMITH, WILLIAM (fl. 1596)
• SMITH, WILLIAM FARRAR (1824—1903)
• SMITH, WILLIAM HENRY (1808—1872)
• SMITH, WILLIAM HENRY (1825—1891)
• SMITH, WILLIAM ROBERTSON (1846-'894)

Smith, Bischof, See also:

• PLATTNER, KARL FRIEDRICH (1800-x858)

Plattner and others, and in more recent times by See also:

• VOGT, KARL CHRISTOPH (1817-1895)

Vogt, Doelter, and at the Geophysical laboratory of the See also:

• CARNEGIE
• CARNEGIE, ANDREW (1837– )

Carnegie Institution, See also:

• WASHINGTON
• WASHINGTON (or WASHINGTON COURT HOUSE)
• WASHINGTON, BOOKER TALIAFERRO (c. 1859– )
• WASHINGTON, BUSHROD (1762-1829)
• WASHINGTON, GEORGE (1732-1799)

Washington . METAL-WORK . Among the many stages in the development of primeval See also:

• MAN
• MAN, ISLE OF (anc. Mona)

man, none can have been of greater moment in his struggle for existence than the See also:

• DISCOVERY

discovery of the metals, and the means of working them . The names generally given to the three prehistoric periods of man's See also:

• LIFE

life on the See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth—the See also:

• STONE
• STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
• STONE, CHARLES POMEROY (1824-1887)
• STONE, EDWARD JAMES (1831-1897)
• STONE, FRANK (1800-1859)
• STONE, GEORGE (1708—1764)
• STONE, LUCY [BLACKWELL] (1818-1893)
• STONE, MARCUS (184o— )
• STONE, NICHOLAS (1586-1647)

Stone, the See also:

• BRONZE

Bronze and the Iron age—imply the vast importance of the progressive steps from the See also:

• FLINT
• FLINT, AUSTIN (1812-1886)
• FLINT, or FLTNTSHTRE (sir Gallestr)
• FLINT, ROBERT (1838- )
• FLINT, TIMOTHY (1780-1840)

flint See also:

• KNIFE (0. E. cuff, a word appearing in different forms in many Teutonic languages, cf. Du. knijf, Ger. Kneif, a shoe-maker's knife, Swed. knif; the ultimate origin is unknown; Skeat finds the origin in the root of " nip," formerly " knip "; Fr. canif is a

knife to the bronze See also:

• CELT
• CELT, or KELT

Celt, and lastly to the keen-edged elastic iron weapon or See also:

• TOOL (0. Eng. tdl, generally referred to a root seen in the Goth. taujan, to make, or in the English word " taw," to work or dress leather)

tool . The metals chiefly used in the arts have been gold, silver, copper and tin (the last two generally mixed, forming an alloy called bronze), iron and lead (see the See also:

• SEPARATE

separate articles on these metals) . Their peculiarities have naturally marked out each of them for special uses and methods of treatment . The durability and the extraordinary ductility and pliancy of gold, its power of being subdivided, See also:

• DRAWN

drawn out or flattened into 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 or See also:

• LEAF (O. Eng. leaf, cf. Dutch loof, Ger. Laub, Swed. lof, &c.; possibly to be referred to the root seen in Gr. Ma-eta, to peel, strip)

leaf of almost See also:

• INFINITE (from Lat. in, not, finis, end or limit; cf. findere, to deave)

infinite fineness, have led to its being used for See also:

• WORKS

works where great minuteness and delicacy of See also:

• EXECUTION (from Lat. ex-sequor, exsecutus, follow or carry out)

execution were required; while its beauty and rarity have, for the most part, limited its use to objects of adornment and luxury, as distinct from those of utility . In a lesser degree most of the qualities of gold are shared by silver, and consequently the treatment of these two metals has always been very similar, though the greater abundance of the latter metal has allowed it to be used on a larger See also:

• SCALE
• SCALE (1) A

scale and for a greater variety of purposes . The great fluidity of bronze when melted, the slightness of its contraction on solidifying, together with its See also:

• DENSITY (Lat. densus, thick)

density and hardness, make it especially suitable for casting, and allow of its taking the impress of the See also:

• MOULD

mould with extreme sharpness and delicacy . In the form of plate it can be tempered and annealed till its See also:

• ELASTICITY

elasticity and toughness are much increased, and it can then be formed into almost any shape under the hammer and See also:

• PUNCH

punch . By other methods of treatment, known to the See also:

• ANCIENT
• ANCIENT (also spelt ANTIENT; derived, through the Fr. ancien, old, from the late Lat. antianum, from ante, before)

ancient Egyptians, Greeks and others, but now forgotten, it could be hardened and formed into knife and See also:

• RAZOR (O.F. razor, mod. rasoir, from racer, to scrape, rase, Late Lat. rasare, frequentative of radere, to scrape)

razor edges of the utmost keenness . In many specimens of ancient bronze, small quantities of silver, lead and zinc have been found, but their presence is probably accidental .

In See also:

• MODERN

modern times See also:

• BRASS
• BRASS (O. Eng. braes)

brass has been much used, chiefly for the See also:

• SAKE

sake of its cheapness as compared with bronze . In beauty, durability and delicacy of surface it is very inferior to bronze, and, though of some commercial importal CE, has been of but little use in the production of works of art . To some extent copper was used in an almost pure state during See also:

• MEDIEVAL

medieval times, especially from the 12th to the 15th See also:

• CENTURY (from Lat. centuria, a division of a hundred men)

century, mainly for objects of ecclesiastical use, such as pyxes, monstrances, reliquaries and croziers, partly on account of its softness under the tool, and also because it was slightly easier to. apply See also:

• ENAMEL (formerly " amel," derived through the Fr. amail, emmll, esmail, from a Latin word smaltum, first found in a 9th-century life of Leo IV.)

enamel and See also:

• GILDING

gilding to pure copper than to bronze (see fig . I) . In the medieval Se