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 (through Fr. from See also:

• LAT

Lat. metallum, mine, See also:

• QUARRY

quarry, adapted from Gr. µATaXAov, in the same sense, probably connected with ,ueraAAdv, to See also:

• SEARCH, or VISIT AND SEARCH

search after, explore, µeTa, after, aAAos, other)  . Originally applied to See also:

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

gold, See also:

• SILVER

silver, See also:

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

copper, See also:

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

iron, See also:

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

tin, See also:

• LEAD
• LEAD (pronounced iced)

lead and See also:

• BRONZE

bronze, i.e. substances having high specific gravity, malleability, opacity, and especially a See also:

• PECULIAR

peculiar lustre, the See also:

• TERM

term " 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 " became generic for all substances with these properties . In See also:

• MODERN

modern See also:

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

chemistry, however, the metals are a See also:

• DIVISION (from Lat. dividere, to break up into parts, separate)

division of the elements, the members of which may or may not possess all these characters . The progress of See also:

• SCIENCE (Lat. scientia, from scire; to learn, know)

science has, in fact, been accompanied by the See also:

• DISCOVERY

discovery of some 70 elements, which may be arranged 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 of their " metallic " properties as above indicated, and it is found that while the end members of the See also:

• SCALE
• SCALE (1) A

scale are most distinctly metallic (or non-metallic), certain central members, e.g. See also:

• ARSENIC (symbol As, atomic weight 75.0)

arsenic, may be placed in either division, their properties approximating to both metallic -and non-metallic . One chemical differentia utilizes the fact that metals always See also:

• FORM (Lat. forma)

form at least one basic See also:

• OXIDE

oxide which yields salts with acids, while non-metals usually form acidic oxides, i.e. oxides which yield acids with See also:

• WATER

water . This See also:

• DEFINITION (Lat. definitio, from de-finire, to set limits to, describe)

definition, however, is highly artificial and objectionable on principle, because when we speak of metals we think, not of their chemical relations, but of a certain sum of See also:

• MECHANICAL

mechanical and See also:

• PHYSICAL

physical properties which unites them all into one natural See also:

• FAMILY

family . All metals, when exposed in an inert See also:

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

atmosphere to a sufficient temperature, assume the form of liquids, which all See also:

• PRESENT

present the following characteristic properties . They are (at least practically) non-transparent; they reflect See also:

• LIGHT

light in a peculiar manner, producing what is called " metallic lustre." When kept in non-metallic vessels they take the shape of a See also:

• CONVEX

convex meniscus . These liquids, when exposed to higher temperatures, some sooner than others, pass into vapours . What these vapours are like is not known in many cases, since, as a See also:

• RULE

rule, they can be produced only at very high temperatures, precluding the use of transparent vessels . Silver vapour is See also:

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

blue, See also:

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

potassium vapour is 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, many others (See also:

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

mercury vapour, for instance) are colourless . The liquid metals, when cooled down sufficiently, some at See also:

• LOWER

lower, others at higher, temperatures freeze into compact solids, endowed with the (relative) non-transparency and the lustre of their liquids .

Thesefrozen metals in See also:

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

general form compact masses consisting of aggregates of crystals belonging to the See also:

• REGULAR

regular or rhombic or (more rarely) the quadratic See also:

• SYSTEM

system . Compared with non-metallic solids, they in general are See also:

• GOOD, JOHN MASON (1764-1827)

good conductors of 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 and of See also:

• ELECTRICITY

electricity . But their most characteristic, though not perhaps their most general, See also:

• PROPERTY

property is that they combine in themselves the apparently incompatible properties of See also:

• ELASTICITY

elasticity and rigidity on the one See also:

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

hand and plasticity on the other . To this remarkable See also:

• COMBINATION (Lat. combinare, to combine)

combination of properties more than to anything else the See also:

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

ordinary metals owe their wide application in the mechanical arts . In former times a high specific gravity used to be quoted as one of the characters of the genus; but this no longer holds, since we now know a See also:

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

series of metals lighter than water . Non-Transparency.—T his, in the See also:

• CASE
• CASE, JOHN (d. 1600)

case of even the solid metals, is perhaps only a very See also:

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

low degree of transparency . In regard to gold this has been proved to be so; gold 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, or thin films of gold produced chemically on 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 plates, transmit light with a green See also:

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

colour . On the other hand, infinitely thin films of silver which can be produced chemically on glass surfaces are absolutely opaque . Very thin films of liquid mercury, according to Melsens, transmit light with a See also:

• VIOLET

violet-blue colour; also thin films of copper are said to be translucent . Colour.—Gold is yellow; copper is red; silver, tin, and some others are pure 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; the See also:

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

majority are greyish . Reflection of Light.—Polished metallic surfaces, like those of other solids, See also:

• DIVIDE

divide any incident See also:

• RAY (Lat. raia)
• RAY (or WRAY, as he wrote his name till 1670), JOHN (1628-1705)

ray into two parts, of which one is refracted while the other is reflected—with this difference, however, that the former is completely absorbed, and. that the latter, in regard to polarization, is quite differently affected . The following values are due to See also:

• RUBENS, PETER PAUL (1577-164o)

Rubens and See also:

• HAGEN
• HAGEN, FRIEDRICH HEINRICH VON DER (178o-1856)

Hagen (See also:

• ANN

Ann. der Phys., 1900, p .

352); they See also:

• EXPRESS (through the French from the past participle of the Lat. exprimere, to press out, by transference used of representing objects in painting or sculpture, or of thoughts, &c. in words)

express the percentage of incident light reflected . The superiority of silver is obvious . Violet . Yellow . Red . Name of Metal . --- X=450 X=550 a=65o Silver 9o•6 9~.5 93'6 See also:

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

Platinum 55.8 61.1 66.3 See also:

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

Nickel 58.5 62.6 65'9 See also:

• STEEL, FLORA ANNIE (1847– )

Steel 58.6 59.4 6o•1 Gold 36.8 74.7 88.2 Copper 48.8 59'5 89 Glass backed with silver 79.3–85.7 82–88 83–89 Glass backed with mercury . 72.8 71.2 71.5 Crystalline Form and Structure.—Most (perhaps all) metals are capable of See also:

• CRYSTALLIZATION

crystallization . The crystals belong to the following systems: regular system—silver, gold, See also:

• PALLADIUM (Gr. sraXXit&ov)
• PALLADIUM [symbol Pd, atomic weight Io6.7 (O=16)]

palladium, mercury, copper, iron, lead; quadratic system—tin, potassium; rhombic system—See also:

• ANTIMONY (symbol Sb, atomic weight 120.2)

antimony, See also:

• BISMUTH

bismuth, See also:

• TELLURIUM [Symbol Te, atomic weight 127.5 (0=16)]

tellurium, See also:

• ZINC

zinc, See also:

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

magnesium . Perhaps all metals are crystalline, only the degree of visibility of the crystalline arrangement is very different in different metals, and even in the same metal varies according to the slowness of solidification and other circumstances . Antimony, bismuth and zinc exhibit a very distinct crystalline structure: a See also:

• BAR
• BAR (0. Fr. barre, Late Lat. barra, origin unknown)
• BAR, CONFEDERATION OF
• BAR, FRANCOIS DE (1538-1606)
• BAR, THE

bar-shaped See also:

• INGOT

ingot readily breaks, and the crystal faces are distinctly visible on the fracture . Tin also is crystalline: a thin bar, when See also:

• BENT
• BENT (E1. BENI)
• BENT, JAMES THEODORE (1852–1897)

bent, " creaks " audibly from the sliding of the crystal faces over one another; but the bar is not easily broken, and exhibits an apparently non-crystalline fracture.—Class I .

Gold, silver, copper, lead, See also:

• ALUMINIUM (symbol Al; atomic weight 27.0)

aluminium, See also:

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

cadmium, iron (pure), nickel and See also:

• COBALT (symbol Co, atomic weight 59)

cobalt are practically amorphous, the crystals (where they exist) being so closely packed as to produce a virtually homogeneous See also:

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

mass.—Class II . The See also:

• GREAT

great contrast in apparent structure between cooled ingots of Class I. and of Class II. appears to be owing chiefly to the fact that, while the latter crystallize in the regular system, metals of Class I. form rhombic or quadratic crystals . Regular crystals expand equally in all directions; rhombic and quadratic expand differently in different directions . Hence, supposing the crystals immediately after their formation to be in See also:

• ABSOLUTE (Lat. absolvere, to loose, set free)

absolute contact with one another all See also:

• ROUND (O. Fr. rond, Lat. rotundus, the Fr. is the source also of Du. rond; Ger., Swed., Dan. and Nor. rond)

round, then, in the case of Class II., such contact will be maintained on cooling, while in the case of Class I. the contraction along a given straight See also:

• LINE

line will in general have different values in any two neighbouring crystals, and the crystals consequently become slightly detached from one another . The crystal-line structure which exists on both sides becomes visible only in the metals of the first class, and only there manifests itself as brittleness . Closely related to the structure of metals is their degree of " plasticity " (susceptibility of being constrained into new forms without See also:

• BREACH (Mid. Eng. breche, derived from the common Teutonic root brec, which appears in " break," Ger. brechen, &c.)

breach of continuity) . This term of course includes as See also:

• SPECIAL

special cases the qualities of " malleability " (capability of being flattened out under the See also:

• HAMMER, FRIEDRICH JULIUS (1810-1862)

hammer) and " ductility " (capability of being See also:

• DRAWN

drawn 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) ; but these two special qualities do not always go parallel to each other, for this See also:

• REASON (Lat. ratio, through French raison)

reason amongst others—that ductility in a higher degree than malleability is determined by the tenacity of a metal . Hence tin and lead, though very malleable, are little ductile . The quality of plasticity is See also:

• DEVELOPED

developed to very different degrees in different metals, and even in the same See also:

• SPECIES

species it depends on temperature, and may be modified by mechanical or physical operations . A bar of zinc, for instance, as obtained by casting, is very brittle; but when heated to See also:

• IOO

ioo° or 15o° C. it becomes sufficiently plastic to be rolled into the thinnest See also:

• SHEET

sheet or to be drawn into wire . Such sheet or wire then remains flexible after cooling, the originally only loosely cohering crystals having got intertwisted and forced into absolute contact with one another—an explanation supported by the fact that rolled zinc has a somewhat higher specific gravity (7.2) than the See also:

• ORIGINAL

original ingot (6.9) . The same metal, when heated to 205° C., becomes so brittle that it can be powdered in a See also:

• MORTAR

mortar .

Pure iron, copper, silver and other metals are easily drawn into wire, or rolled into sheet, or flattened under the hammer . But all these operations render the metals harder, and detract from their plasticity . Their original softness can be restored to them by ' See also:

• ANNEALING, HARDENING AND

annealing,” i.e. by See also:

• HEATING

heating them to redness and then quenching them in 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 water . In the case of iron, however, this applies only if the metal is perfectly pure . If it contains a few parts of See also:

• CARBON (symbol C, atomic weight 12)

carbon per thousand, the annealing See also:

• PROCESS

process, instead of softening the metal, gives it a " 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,” meaning a higher degree of hardness and elasticity (see below) . What we have called plasticity must not be confused with the notion of " softness, which means the degree of facility with which the plasticity of a metal can be discounted . Thus lead is far softer than silver, and yet the latter is by far the more plastic of the two . The famous experiments of H . E . Tresca show that the plasticity of certain metals at least goes consider-ably farther than had before been supposed . He operated with lead, copper, silver, iron and some other metals . Round disks made of these substances were placed in a closely fitting cylindrical cavity drilled in a See also:

• BLOCK
• BLOCK (from the Fr. bloc, and possibly connected with an Old Ger. Block, obstruction, cf. " baulk ")
• BLOCK, MAURICE (1816–19or)

block of steel, the cavity having a circular See also:

• APERTURE (from Lat. aperire, to open)

aperture of two or four centimetres below .

By an See also:

• HYDRAULIC

hydraulic See also:

• PRESS (through Fr. presse from Lat. pressare, frequentative of premere, to crush, squeeze, press)

press a pressure of 1oo,000 kilos was made to See also:

• ACT (Lat. actus, actum)

act upon the disks, when the metal was seen to " flow " out of the hole like a viscid liquid . In spite of the immense rearrangement of parts there was no breach of continuity . What came out below was a compact See also:

• CYLINDER (Gr. KvAwSpos, from KvXivaety, to roll)

cylinder with a rounded bottom, consisting of so many layers super-imposed upon one another . Parallel experiments with layers of dough or See also:

• SAND
• SAND, GEORGE (1804-1876)

sand plus some connecting material proved that the particles in all cases moved along the same tracks as would be followed by a flowing cylinder of liquid, Of the better known metals potassium and See also:

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

sodium are the softest; they can be kneaded between the fingers like See also:

• WAX

wax . After these follow first See also:

• THALLIUM

thallium and then lead, the latter being the softest of the metals used in the arts . Among these the softness decreases in about the following order: lead; pure silver, pure gold, tin, copper, aluminium,platinum, pure. iron . As liquidity might be looked upon as the tie plus ultra of softness, this is the right See also:

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

place for stating that, while most metals, when heated up to their melting points, pass See also:

• PRETTY

pretty abruptly from the solid to the liquid See also:

• STATE
• STATE, GREAT OFFICERS OF

state, platinum and iron first assume, and throughout a See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long range of temperatures retain, a See also:

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

condition of viscous semi-solidity which enables two pieces of them to be " welded " together by pressure into one continuous mass . According to Prechtl, the ordinary metals, in regard to the degree of facility or perfection with which they can be hammered See also:

• FLAT (a modification of O. Eng. flet, an obsolete word of Teutonic origin, meaning the ground beneath the feet)

flat on the See also:

• ANVIL (from Anglo-Saxon anfilt or onfilti, either that on which something is " welded " or " folded," cf. German falzen, to fold, or connected with other Teutonic forms of the word, cf. German amboss, in which case the final syllable is from " beat," and

anvil, rolled out into sheet, or drawn into wire, form the following descending series: Hammering . See also:

• ROLLING

Rolling into Sheet . See also:

• DRAWING

Drawing into Wire . Lead . Gold .

Platinum . Tin . Silver . Silver . Gold . Copper . Iron . Zinc . Tin . Copper . Silver . Lead .

Gold . Copper . Zinc . Zinc . Platinum . Platinum . Tin . Iron . Iron . Lead . To give an See also:

• IDEA (Gr. Ibia, connected with i&eiv, to see; cf. Lat. species from specere, to look at)

idea of what can be done in this way, it may be stated that gold can be beaten out to leaf of the thickness of$'~ mm.; and that platinum, by judicious See also:

• WORK

work, can be drawn into wire 20 00 mm. thick . 199 By the " hardness " of a metal we mean the resistance which it offers to the See also:

• FILE

file` or engraver's 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 Taking it in this sense, it does not necessarily. measure,. e.g. the resistance of a metal to See also:

• ABRASION (from Lat. ab, off, and radere, to scrape)

abrasion by See also:

• FRICTION (from Lat. fricare, to rub)

friction .

Thus, for instance, le% aluminium bronze is scratched by an ordinary 'steel 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-blade, yet the sets of needles used for perforating See also:

• POSTAGE

postage stamps last longer if, made of aluminium bronze than if made of steel . Elasticity.—All metals are elastic to this extent that a See also:

• CHANGE (derived through the Fr. from the Late Lat. cambium, cambiare, to barter; the ultimate derivation is probably from the root which appears in the Gr. «a urmu', to bend)

change of form, brought about by stresses not exceeding certain limit values, will disappear on the stress being removed . Strains exceeding the " limit of elasticity " result in permanent deformation, or (if sufficiently great) in rupture . Referring the reader to the See also:

• ARTICLE (from Lat. articulus, a joint)

article ELnsTICITY for the theoretical and to the STRENGTH OF MATERIALS for the See also:

• PRACTICAL

practical aspects of this subject, we give here a table of the " modulus of elasticity, ' E (See also:

• COLUMN (Lat. columna)

column 2), for millimetre and kilogramme . Hence See also:

• I000

i000/E is the See also:

• ELONGATION

elongation in millimetres per See also:

• METRE ((terpuc?, sc. rFxvf, from Gr. Or poi', measure)

metre length per kilo . Column 3 shows the See also:

• CHARGE
• CHARGE (through the Fr. from the Late Lat. carricare, to load in a carrus or wagon; cf. " cargo ")

charge causing a permanent elongation of 0.05 mm. per metre, which, for practical purposes, Wertheim takes as giving the limit of elasticity; column 4 gives the breaking See also:

• STRAIN (through O. Fr. straindre, estraindre, mod. i treindre, from Lat. stringere, to draw tight, related to stress, stretch, string, &c.)

strain . These values may vary within certain limits for different specimens . Name of Metal . E . For Wire of r sq. mm . See also:

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

Section, See also:

• WEIGHT

Weight (in Kilos) causing Permanent Breakage . Elongation of gabs- Lead, drawn 1,803 0.25 2+1 „ annealed 1,727 0.20 1.8 Tin, drawn .

. . 4,148 0.45 2.45 „ annealed 1,700 0.20 Cadmium . 7,070 2.24 Gold, drawn . , , . 8,x31 13.5 27 Silver,i drawn . . 7,357 11.3 ' 29 „ annealed . , , 7,140 2.6 16 Zinc, pure, 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 in See also:

• MOULD

mould . 9,021 ,, ordinary, drawn 8,735 0.75 13 Palladium, drawn . 11,759 18 annealed 9,709 under 5 27 Copper, drawn . . , . 12,449 12 40 „ annealed . 10,519 under 3 30 Platinum wire, See also:

• MEDIUM

medium 17,004 26 34 thickness, drawn .

. Platinum, annealed , . 15,518 14 23 Iron, drawn 20,869 32 61 . . . 20,794 under 5 . 47 annealed . . , . Nickel, drawn . , , . 23,950 X61 Aluminium 7,200 ,, bronze , . 10,700 See also:

• BRASS
• BRASS (O. Eng. braes)

Brass (ZnCu2) , . 8,543 See also:

• GERMAN
• GERMAN, DUTCH AND SCANDINAVIAN

German silver (Zn,Cu,2Nii) 10,788 . Specific Gravity.—This varies in metals from •594 (See also:

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

lithium) to 22'48 (See also:

• OSMIUM [symbol Os., atomic weight 190.9 (0= r6)]

osmium), and in one and the same species is a See also:

• FUNCTION

function of temperature and of previous physical and mechanical treatment .

It has in general one value for the powdery metal as obtained by reduction of the oxide in See also:

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

hydrogen below the melting point of the metal, another for the metal in the state which it assumes spontaneously on freezing, and this latter value, in general, is modified by hammering, rolling, drawing, &c . These mechanical operations do not necessarily add to the See also:

• DENSITY (Lat. densus, thick)

density; stamping, it is true, does so necessarily, but rolling or drawing occasionally causes a diminution of the density . Thus, for instance, chemically pure iron in the ingot has the specific gravity 7.844; when it is rolled out into thin sheet, the value falls to 7.6; when drawn into thin wire, to 7.75 . The following table gives the specific gravities of many metals . Where special statements are not made, the See also:

• NUMBERS, BOOK OF
• NUMBERS, PARTITION OF

numbers hold for the ordinary temperature (15° to 17° or 20° C.), referred to water of the same temperature as a See also:

• STANDARD
• STANDARD, BATTLE OF THE

standard, and to hold for the natural frozen metal . Name of Metal . Specific Gravity . Lithium ' •594 Potassium .875 Sodium •978 See also:

• RUBIDIUM [symbol Rb, atomic weight 85.45 (0=16)]

Rubidium I.52 . See also:

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

Calcium I .578 Magnesium 1.743 See also:

• CAESIUM (symbol Cs, atomic weight 132.9)

Caesium 1.88 See also:

• BERYLLIUM

Beryllium .. . 2.1 See also:

• STRONTIUM [Symbol Sr, atomic weight 87.62 (0=16)]

Strontium . . . . 2.5 • Aluminium, pure, ingot 2.583 at 4° " ordinary, hammered .

2.67 Name of Metal . Specific Gravity . See also:

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

Barium 3.75 See also:

• ZIRCONIUM

Zirconium . . 4.15 See also:

• VANADIUM

Vanadium, See also:

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

powder 5'5 See also:

• GALLIUM (symbol Ga; atomic weight 69.9)

Gallium 5.95 Lanthanum 6.163 See also:

• CERIUM (symbol Ce, atomic weight 140.25)

Cerium 6.68 Antimony 6.62 See also:

• CHROMIUM (symbol Cr. atomic weight 52.1)

Chromium 6.50 Zinc, ingot 6.915 , rolle gut 7.2 See also:

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

Manganese 7.39 Tin, cast 7.29 to 7.299 ,, crystallized by See also:

• ELECTROLYSIS (formed from Gr. Xbety, to loosen)

electrolysis from solutions 7.178 See also:

• INDIUM (symbol In, atomic weight 114.8)

Indium 7.42 Iron, chemically pure, ingot 7.844 thin sheet 7.6 wrought, high quality 7.8 to 7.9 Nickel, ingot 8.279 , forged 8.666 Cadmium, ingot 8.546 hammered 8.667 Cobalt . . . 8.6 See also:

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

Molybdenum, containing 4 to 5 % of carbon . 8.6 Copper, native 8.94 ,, cast .8.92 wire or thin sheet 8.94 to 8.95 electrotype, pure 8.945 Bismuth 9.823 at 12° Silver, cast 10.4 t0 10.5 , stamped 10.57 Lead, very slowly frozen . . . . 11.254 ,, quickly frozen in cold water 11.363 Palladium 11.4 at 22.5° Thallium 11.86 See also:

• RHODIUM [symbol Rh; atomic weight 102.9 (0=16)]

Rhodium 12.1 See also:

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

Ruthenium 12.26 at 0° Mercury, liquid 13.595 at.o° See also:

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

Tungsten, compact, by H2 from chloride 14 39 below-40° vapour . 16'54 as reduced by hydrogen, powder 19.13 See also:

• URANIUM [symbol U, atomic weight 238.5 (0=16)]

Uranium 18.7 Gold, ingot 19.265 at -13 ° stamped . . . . 19.31 to 19.34 powder, precipitated by ferrous sul- 19'55 to 19.72 See also:

• PHATE

phate .

. 21.50 . Platinum, pure See also:

• IRIDIUM (symbol Ir.; atomic weight 193.1)

Iridium . . . 22.2 Osmium 22.477 Thermal Properties.-The specific heats of most metals' have been determined . The general result is that, conformably with See also:

• DULONG, PIERRE LOUIS (1785—1838)

Dulong and See also:

• PETIT, SIR DINSHAW MANECKJI, BART

Petit's See also:

• LAW
• LAW (0. Eng. lagu, M. Eng. lawe; from an old Teutonic root lag, " lie," what lies fixed or evenly; cf. Lat. lex, Fr. loi)
• LAW, JOHN (1671—1729)
• LAW, WILLIAM (1686-1761)

law, the " atomic heats " all come to very nearly the same value (of about 6.4) ; i.e. atomic weight by specific heat =6.4 . Thus we have for silver by theory 6.4/108 =•0593, and by experiment .0570 for Io° to too° C . The expansion by heat varies greatly . The following table gives the linear expansions from o° to too C. according to See also:

• FIZEAU, ARMAND HIPPOLYTE LOUIS (1819–1896)

Fizeau (Comptes rendus, lxviii . 1125), the length at o° being taken as unity . Name of Metal . Expansion . o° to 10o° .

Platinum, cast •oo0 907 Gold, cast •001 451 Silver, cast .00t 936 Copper, native, from See also:

• LAKE
• LAKE, GERARD LAKE, 1ST VISCOUNT (1744-1808)

Lake See also:

• SUPERIOR

Superior •ooi 708 artificial .00t 869 Iron, soft, as used for electromagnets , 228 ,, reduced by hydrogen and compressed •ooi 208 Cast steel, See also:

• ENGLISH

English annealed •ooi See also:

• ITO, HIROBUMI, PRINCE (1841-1909)

Ito Bismuth, in the direction of the See also:

• AXIS (Lat. for " axle ")

axis •ooi 642 ,, at right angles to axis .00t 239 „ mean expansion, calculated .00t 374 Tin, of Malacca, compressed powder •002 269 Lead, cast •002 948 Zinc, distilled, compressed powder •002 905 Cadmium, distilled, compressed powder •003 102 Aluminium, cast •002 . 336 Brass (71.5 %copper, 28.5 %zinc) •ooi 879 Bronze (86.3 % copper, 9.7 % tin, 4.0 % zinc) •001 802 The coefficient of expansion is See also:

• CONSTANT, BENJAMIN (1845-1902)

constant for such metals only as crystallize in the regular system ; the others expand differently in the directions of. the different axes . To eliminate this source ofuncertainty these metals were employed as compressed powders . The cubical expansion- of mercury from o° to too° C. is .018153 710 -87 (See also:

• REGNAULT, HENRI (1843-1871)
• REGNAULT, HENRI VICTOR (1810-1878)
• REGNAULT, JEAN BAPTISTE (1754-1829)

Regnault).(See See also:

• THERMOMETRY (Gr. Bepµos, warm; µerpov, a measure)

THERMOMETRY.) sibility and Volatility.-The fusibility in different metals is very different, as shown by the following table, which, besides including all the fusing points (in degrees C.) of metals which have been determined numerically, indicates those of a selection of other metals by the positions assigned to them in the table . Name of Metal . Melting Point . Boiling Point . Mercury -38.8 357.3 Caesium 26-27 Gallium 3o.I Rubidium 38.5 Potassium 62.5 719-731 Sodium 95.6 861-954 Indium 155 Lithium 180.o Tin 231'9 1450-1600 Bismuth 269 z 1090-1450 Thallium 290 Cadmium 320.7 78o Lead 327.7 1450-1600 Zinc' 419 929-954 Incipient red heat 525 Antimony 629.5 Magnesium . 632.6 about Imo Aluminium 655 See also:

• CHERRY

Cherry red heat 700 Calcium 78o Lanthanum 810 Barium 85o Sillier 962 Gold 1064 Copper' t082 2100 O per Yellow heat t t oo Iron 1300-1400 Nickel , . . Cobalt 1800(?) Dazzling while heat . . 1500-1600 Palladium 1500 . Platinum 176o Rhodium above-Pt .

Iridium . „ 2200 Ruthenium ` Ir . . . . . . . In . el See also:

• TANTALUM [symbol Ta, atomic weight 181•o (0=16)]

Tantalum electric Osmium See also:

• FURNACE

furnace For practical purposes the volatility of metals may be stated as follows:- I . Distillable below redness:. mercury . 2 . Distillable at red heats: cadmium, See also:

• ALKALI

alkali metals, zinc, magnesium . 3, Volatilized more or less readily when heated beyond their fusing points in open crucibles: - antimony (very readily), lead, bismuth, tin, silver . 4 . Barely so: gold, (copper) .

5 . Practically non-volatile: (copper), iron, nickel, cobalt, aluminium; also lithium, barium, strontium and calcium . In the oxyhydrogen #fame silver boils, forming a blue vapour, while platinum volatilizes slowly, and osmium, though infusible, very readily . Latent Heats of Liquefaction.-Of these we know little . The following numbers are due to See also:

• PERSON, OFFENCES AGAINST THE

Person-See also:

• ICE (a word common to Teutonic languages; cf. Ger. Eis)

ice, it may be stated, being 80 . Name of Metal, Latent Name of Metal . Latent Heat . Heat . Mercury . . . 2.82 Cadmium . . .

13.6 Lead . . . . 5.37 Silver 21.1 Bismuth 12.4 Zinc 28.1 The latent heat of See also:

• VAPORIZATION

vaporization of mercury was found by Marigna to be 103 to 106 . Conductivity.-Conductivity, whether thermic or electric, is very differently developed in different metals; and, as an exact knowledge of these conductivities is of great importance, much See also:

• ATTENTION (from Lat. ad-tendo, await, expect; the condition of being " stretched " or " tense ")

attention has been given to their numerical determination (see See also:

• CONDUCTION, ELECTRIC

CONDUCTION, ELECTRIC; and CONDUCTION OF HEAT) . The following table gives the electric conductivities of a number of metals as determined by Matthiesen, and the relative See also:

• INTERNAL

internal thermal conductivities of (nominally) the same metals as determined by See also:

• WIEDEMANN, GUSTAV HEINRICH (1826-1899)

Wiedemann and See also:

• FRANZ, ROBERT (1815-1892)

Franz, with rods about 5 mm. thick, of which one end was kept at too° C., the See also:

• REST (O. Eng. rest, reste, bed, cognate with other Teutonic forms, e.g. Ger. Rast, Riiste, rest, and probably Gothic Rasta, league, i.e. resting or stopping place)

rest of the See also:

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

rod in a " vacuum " (of 5 mm. tension) at 12° C . Matthiesen's results, except in the two cases noted, are from his memoir in Pogg . Ann., 1858, ciii . 4213 Relative Conductivities . Name of Metal . - ` Electric . Thermic . Copper, commercial, No .

3 . . . .774 at 18.8° No . 2 •721 ,, 22.6 „ chemically pure, hard drawn •93 1 Copper •748 Gold, pure .552 „ 21.8 .548 „ absolutely pure •73 ,, 19•o Brass .25 Tin, pure .115 „ 21.0 •154 See also:

• PIANOFORTE (Ital. piano, soft, and forte, loud)

Pianoforte wire .144 ,, 20.4 Iron rod • I01 Steel .103 Lead, pure •0777 ,, 17.3 •079 Platinum .105 „ 20.7 .094 German silver .0767 „ 18.7 .073 Bismuth •0119 „ I3'8 Aluminium .196 „ 19.6 Mercury .0163 „ 22.8 Silver, pure 1 •000 „ 0 1 •000 Magnetic Properties: Iron, nickel and cobalt are the only metals which are attracted by the magnet and can become magnets them-selves . But in regard to their See also:

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

power of retaining their See also:

• MAGNETISM
• MAGNETISM, TERRESTRIAL

magnetism none of them comes at all up to the See also:

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

compound metal steel . See MAGNETISM . Chemical Changes.—Metals may unite chemically both with metals and with non-metals . The compounds formed in the first case, which may be either definite chemical compounds or solid solutions, are discussed under See also:

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

ALLOYS; in this place only combinations with non-metals are discussed, it being premised that the See also:

• FREE

free metal takes See also:

• PART

part in the reaction . Metallic Substances Produced by the See also:

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

Union of Metals with Small Proportions of Non-Metallic Elements . Hydrogen, as was shown by See also:

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

Graham, is capable of uniting with or being occluded by certain metals, notably with palladium (q.v.), into metal-like compounds . See also:

• OXYGEN (symbol 0, atomic weight 16)

Oxygen,—Mercury and copper and some other metals are capable of dissolving their own oxides . Mercury, by, doing so, becomes viscid and unfit for its ordinary applications .

Copper, when pure to start with, suffers considerable deterioration in plasticity . But the presence of moderate proportions of cuprous oxide has been found to correct the evil See also:

• INFLUENCE (Late Lat. influentia, from influere, to flow in)

influence of small contaminations by arsenic, antimony, lead and other See also:

• FOREIGN

foreign metals . Commercial coppers sometimes owe their good qualities to this compensating influence . Arsenic combines readily with all metals into true arsenides, which latter, in general, are soluble in the metal itself . The presence in a 'metal of even small proportions of arsenide generally leads to considerable deterioration in mechanical qualities . See also:

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

Phosphorus.—The remark just made might be said to hold for phosphorus were it not for the existence of what is called " phosphorus-bronze,” an alloy of copper with phosphorus (i.e. its own phosphide), which possesses valuable properties . According to See also:

• ABEL (better ABELL), THOMAS (d. 1540)
• ABEL (Hebrew for breath)
• ABEL, KARL FRIEDRICH (1725-1787)
• ABEL, NIELS HENRIK (1802-1829)
• ABEL, SIR FREDERICK AUGUSTUS, BART

Abel, the most favourable effect is produced by from I to 1i /° of phosphorus . Such an alloy can be cast like ordinary bronze, but excels the latter in hardness, elasticity, toughness and tensile strength . Carbon.—Most metals when molten are capable of dissolving at least small proportions of carbon, which, in general, leads to a deterioration in metallicity, except in the case of iron, which by the addition of small percentages of carbon gains in elasticity and tensile strength with little loss of plasticity (see IRON) . See also:

• SILICON [symbol Si, atomic weight 28.3 (0= 16)]

Silicon, so far as we know, behaves to metals pretty much like carbon, but our knowledge of facts is limited . What is known as cast iron is essentially an alloy of iron proper with 2 to 6 % of carbon and more or less of silicon (see IRON) . Alloys of copper and silicon were prepared by Deville in 1863 .

The alloy with 12 % of silicon is white, hard and brittle . When diluted down to 4.8 %, it assumes the colour and fusibility of bronze, but, unlike it, is tenacious and ductile like iron . See also:

• ACTION

Action of the More Ordinary Chemical Agents on See also:

• SIMPLE

Simple Metals . In the case of See also:

• GROUP

group I the action is more or less violent, and the hydroxides formed are soluble in water and very strongly basic; metals of group 2 are only slowly attacked, with formation of relatively feebly basic and less soluble hydroxides . Disregarding the rarer elements, the metals not named so far may be said to be See also:

• PROOF (in M. Eng. preove, proeve, preve, &°c., from O. Fr . prueve, proeve, &c., mod. preuve, Late. Lat. proba, probate, to prove, to test the goodness of anything, probus, good)

proof against the action of pure water in the See also:

• ABSENCE (Lat. absentia)

absence of free oxygen (See also:

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

air) . By the See also:

• JOINT (through Fr. from Lat. junctum, jungere, to join)

joint action of water and air, thallium, lead, bismuth are oxidized, with formation of more or less sparingly soluble hydroxides (ThHO, PbH2O,, BiH3O3), which, in the presence of carbonic See also:

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

acid, pass into still less soluble basic See also:

• CARBONATES

carbonates.' Iron, when exposed to moisture and air, " rusts "; but this process never takes place in the absence of air, and it is questionable whether it ever sets in in the absence of carbonic acid (see 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) . Copper, in the present connexion, is intermediate between iron and the following group of metals . Mercury, if pure, and all the " See also:

• NOBLE, SIR ANDREW (1832- )

noble " metals (silver, gold, platinum and platinum-metals), are absolutely proof against water even in the presence of oxygen and carbonic acid . The metals grouped together above, under and 2, act on See also:

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

steam pretty much as they do on liquid water . Of the rest, the following are readily oxidized by steam at a red heat, with formation of hydrogen See also:

• GAS

gas—zinc, iron, cadmium, cobalt, nickel, tin . Bismuth is similarly attacked, but slowly, at a white heat . Aluminium is barely affected even at a white heat, if it is pure; the ordinary impure metal is liable to be very readily oxidized .

Aqueous Sulphuric or Hydrochloric Acid readily dissolves See also:

• GROUPS
• GROUPS, THEORY

groups I and 2, with See also:

• EVOLUTION

evolution of hydrogen" and formation of chlorides or sulphates . The same holds for the following group (A) : [manga'-nese, zinc, magnesium] iron, aluminium, cobalt, nickel, cadmium . Tin dissolves readily in strong hot hydrochloric acid as SnC12; aqueous sulphuric acid does not act on it appreciably in the cold'; at 15o° it attacks it more or less quickly, according to the strength of the acid, with evolution of sulphuretted hydrogen or, when the acid is stronger, of sulphurous acid gas and deposition of See also:

• SULPHUR

sulphur (See also:

• CALVERT
• CALVERT, FREDERICK CRACE (1819–1873)
• CALVERT, SIR HARRY, BART

Calvert and See also:

• JOHNSON, ANDREW
• JOHNSON, ANDREW (1808–1875)
• JOHNSON, BENJAMIN (c. 1665-1742)
• JOHNSON, EASTMAN (1824–1906)
• JOHNSON, REVERDY (1796–1876)
• JOHNSON, RICHARD (1573–1659 ?)
• JOHNSON, RICHARD MENTOR (1781–1850)
• JOHNSON, SAMUEL (1709-1784)
• JOHNSON, SIR THOMAS (1664-1729)
• JOHNSON, SIR WILLIAM (1715–1774)
• JOHNSON, THOMAS

Johnson) . A group (B), comprising copper, is, substantially, attacked only in the presence of oxygen or air . Lead, in sufficiently dilute acid, or in stronger acid if not too hot, remains unchanged . A group (C) may be formed of mercury, silver, gold and platinum, which are not touched by either aqueous acid in any circumstances . Hot (concentrated) sulphuric acid does not attack gold, platinum and platinum-metals generally; all other metals (including silver) are converted into sulphates, with evolution of sulphur dioxide . In the case of iron, ferric sulphate, Fe2(SO4)3, is produced; tin yields a somewhat indefinite sulphate of its oxide SnO2 . Nitric Acid (Aqueous)—Gold, platinum, iridium and rhodium only are proof against the action of this powerful oxidizer . Tin and antimony (also arsenic) are converted by it (ultimately) into hydrates of their highest oxides SnO2, Sb206 (As20s)—the oxides of tin and antimony being insoluble in water and in the acid itself . All other metals, including palladium, are dissolved as nitrates, the oxidizing part of the reagent being generally reduced to oxides of See also:

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

nitrogen . Iron, zinc, cadmium, also tin under certain conditions, reduce the dilute acid, partially at least, to nitrous oxide, N20, or ammonium nitrate, NH4NO3 .

Aqua Regia, a mixture of nitric and hydrochloric acids, converts all metals (even gold, the " See also:

• KING
• KING (O. Eng. cyning, abbreviated into cyng, cing; cf. O. H. G. chun- kuning, chun- kunig, M.H.G. kiinic, kiinec, kiinc, Mod. Ger. Konig, O. Norse konungr, kongr, Swed. konung, kung)
• KING [OF OCKHAM], PETER KING, 1ST BARON (1669-1734)
• KING, CHARLES WILLIAM (1818-1888)
• KING, CLARENCE (1842–1901)
• KING, EDWARD (1612–1637)
• KING, EDWARD (1829–1910)
• KING, HENRY (1591-1669)
• KING, RUFUS (1755–1827)
• KING, THOMAS (1730–1805)
• KING, WILLIAM (1650-1729)
• KING, WILLIAM (1663–1712)

king of metals,” whence the name) into chlorides, except only rhodium, iridium and ruthenium, which; when pure, are not attacked . See also:

• CAUSTIC (Gr. rcavvraubs, burning)

Caustic Alkalis.—Of metals not decomposing liquid pure water, only a few dissolve in aqueous caustic potash or soda, with evolution of hydrogen . The most important of these are aluminium and zinc, which are converted into aluminate, AI(OK,Na)3, and zincate, Zn(OK,Na)2, respectively . But of the rest the majority, when treated with boiling sufficiently strong alkali, are attacked at least superficially; of ordinary metals only gold, platinum, and silver are perfectly proof against the reagents under See also:

• CONSIDERATION (from Lat. considerare, to look at closely, examine, generally taken to be from con-, and the base seen in sidus, sideris, a star, the word being supposed to be originally an astrological or astronomical term)

consideration, and these accordingly are used preferably for the construction of vessels intended for See also:

• ANALYTICAL

analytical operations involving the use of aqueous caustic alkalis . For commercial purposes iron is universally employed and See also:

• WORKS

works well; but it is not available analytically, because a superficial oxidation of the empty part of the See also:

• VESSEL (O. Fr. vaissel, from a rare Lat. vascellum, dim. of vas, vase, urn)

vessel (by the water and air) cannot be prevented . Basins made of pure malleable nickel are free from this See also:

• DRAWBACK

drawback; they work as well as platinum, and rather better than silver ones do . There is hardly a single metal which holds out against the alkalis themselves when in the state of.fiery See also:

• FUSION

fusion; even platinum is most violently attacked . In chem'$ral laboratories fusions with caustic alkalis are always effected in vessels made of gold or silver, these metals holding out fairly well even in the presence of air . Gold is the better of the two . Iron, which stands so well against aqueous alkalis, is most violently attacked by the fused reagents . Yet tons of caustic soda are fused daily in chemical works in iron pots without thereby suffering contamination, which seems to show that (clean) iron, like gold and silver, is at-tacked only by the joint action of fused alkali and air, the influence of the latter being of course minimized in large-scale operations . Oxygen or Air.—The noble metals (from silver upwards) do not combine directly with oxygen given as oxygen gas (02), although, like silver, they may absorb this gas largely when in the fused condition, and may not be proof against See also:

• OZONE

ozone, Oa .

Mercury, within The metals to be referred to are always understood to be given in the compact (frozen) condition, and that, wherever metals are enumerated as being similarly attacked, the degree of readiness in the action is indicated by the order in which the several members are named—the more readily changed metal always See also:

• STANDING

standing first . Water, at ordinary or slightly elevated temperatures, is decomposed more or less readily, with evolution of hydrogen gas and formation of a basic See also:

• HYDRATE

hydrate, by (1) potassium (formation of KHO), sodium (NaHO), lithium (LiOH), barium, strontium, calcium (BaH2O2, &c.) ; (2) magnesium, zinc, manganese (MgO2H2, &c.) . 1 Published in 186o, and declared by Matthiesen to be more exact than the old numbers . a certain range of temperatures situated See also:

• CLOSE
• CLOSE (from Lat. clausum, shut)
• CLOSE, MAXWELL HENRY (1822-1903)

close to its boiling point, combines slowly with oxygen into the red oxide, which, however, breaks up again at higher temperatures . All other metals, when heated in oxygen or air, are converted, more or less readily, into See also:

• STABLE

stable oxides . Potassium, for example, yields peroxide, K202 or K2O4; sodium gives Na202; the barium-group metals, as well as magnesium, cadmium, zinc, lead, copper, are converted into their monoxides MeO . Bismuth and antimony give (the latter very readily) sesquioxide (Bi203 and Sb203, the latter being capable of Passing into Sb204) . Aluminium, when pure and kept out of contact with siliceous See also:

• MATTER

matter, is only oxidized at a white heat, and then very slowly, into alumina, Al20, . Tin, at high temperatures, passes slowly into oxide, SnO2 . Sulphur.—Amongst the better known metals, gold and aluminium are the only ones which, when heated with sulphur or in sulphur vapour remain unchanged . All the rest, under these circumstances, are converted into sulphides . The metals of the alkalis and alkaline earths, also magnesium, See also:

• BURN, RICHARD (1709-1785)

burn in sulphur vapour as they do in oxygen .

Of the heavy metals, copper is the one which exhibits by far the greatest avidity for sulphur, its subsulphide Cu2S being the stablest of all heavy metallic sulphides in opposition to dry reactions . See also:

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

Chlorine.—All metals, when treated with chlorine gas at the proper temperatures, pass into chlorides . In some cases the chlorine is taken up in two instalments, a lower chloride being produced first, to pass ultimately into a higher chloride . Iron, for instance, is converted first into FeCl2, ultimately into FeCls, which practically means a mixture of the two chlorides, or pure FeCls as a final product . Of the several products, the chlorides of gold and platinum (AuCla and PtCla) are the only ones which when heated beyond their temperature of formation dissociate into metal and chlorine . The ultimate chlorination product of copper, CuCl2, when heated to redness, decomposes into the lower chloride, CuCl, and chlorine . All the rest, when heated by themselves, volatilize, some at lower, others at higher temperatures . Of the several individual chlorides, the following are liquids or solids, volatile enough to be distilled from glass vessels: AsCla, SbCla, SnC1a, BiCla, HgC12, the chlorides of arsenic, antimony, tin, bismuth, mercury respectively . The following are readily volatilized in a current of chlorine, at a red heat: AIC13, CrCls, FeCl3, the chlorides of aluminium, chromium, iron . The following, though volatile at higher temperatures, are not volatilized at dull redness: KC1, NaCl, LICI, NiC12, CoC12, MnC12, ZnCl2, MgCl2, PbC12, AgCl, the chlorides of potassium, sodium, lithium, nickel, cobalt, manganese, zinc, magnesium, lead, silver . Somewhat less volatile than the last-named group are the chlorides (MC12) of barium, strontium and calcium . Metallic chlorides, as a class, are readily soluble in water .

The following .are the most important exceptions: silver chloride, AgCl, and mercurous chloride, HgCl, are absolutely insoluble; lead chloride, PbC12, and cuprous chloride, CuCI, are very sparingly soluble in water . The chlorides AsCla, SbCls, BiCls, are at once decomposed by (liquid) water, with formation of oxide (As20s) or oxychlorides (SbOCI, . BiOCI) and hydrochloric acid . The chlorides MgCl2, AlCls, CrCla, FeCla, suffer a similar decomposition when evaporated with water in the heat . The same holds in a limited sense for ZnCl2, CoC12, NiCl2, and even CaC12 . All chlorides, except those of silver and mercury (and, of course, those of gold and platinum), are oxidized by steam at high temperatures, with elimination of hydrochloric acid . For the characters of metals as chemical elements see the special articles on the different metals . See generally A . Rossing Geschichte der Metalle (1901); B . See also:

• NEUMANN, FRANZ ERNST (1798-1895)
• NEUMANN, KARL FRIEDRICH (1793-1870)

Neumann, See also:

• DIE
• DIE (Fr. de, from Lat. datum, given)

Die Metalle (1904); also See also:

• TREATISES

treatises on chemistry .