A Rudimentary Treatise on the Metallurgy of Copper: Being a Concise Introduction to the Methods ...

Robert H. Lamborn · 1860 · Historical

A Rudimentary Treatise on the Metallurgy of Copper: Being a Concise Introduction to the Methods ... by Robert H. Lamborn (1860). Full text and reference in…

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The

Metalluegt Of Copper.

A Rudimentary Treatise

On The

[Etalluegy Of Copper.

Being A

Concise Inteoduction

To The

Methods Of Seeking, Mining, Dressing, Assaying,

And Smelting The Ores Of Copper And

Manufacturing Its Alloys;

Together With Historical And Statistical Notices

Of The Metal.

By

Dr. ROBERT H. LAMBORN,

Cor. M. Imperial Royal Geo. Reichsanstalt, Viepjiaj Acad. Nat. Sci. Fhilada.

'

London : "In Weale, 59, High Holboen.

C-"

The Vew V

PUBLIC LlBr.

ft 19 ::

Biudbury And Kvans, Printers, Whitefriar8.

Preface.

The Anglo-SaTon nations exceed all other in tte md amount of the metals and minerals they . year bring into commerce, j'et tlieir literature ; of the methods by which these subterranean isores are raised and made valuable is small and In aaatisfactory.

Tlie Author does not expect within the compass of a

reatise of this size to do much towards extendioi

literature, but he ventures to believe that by

nishing in a condensed form, the principles of the

illurgy of copper, and a description and esplana-

the latest and most important means of

ering-'.Rnd Tedflcflig; thfe.- Wes of that valuable

step" h'Bt'epj,_t.d ji .condition suited for the

wses of thWapfjutpjaXf — he will supply a source

informatioti f(;.Wtie1j -Eriglish smelters, students

IBd artisans, fiaYErlbflgiouglit.'

, concluding this volume the Author cannot omit ning his thanks to the owners and officers of

Wfl sad lurnnccs upon t\iVa aivi <:fCacs.

1 Preface.

side of the Atlantic for the uniform courtesy they have extended to him and to mention the foUowing excellent works and papers firom which he has drawn material in the preparation of the accompanying chapters :

Muspratt'a Chemistry applied to the Arts."

PhiUips' Manual of Metallurgy."

Napier," in the London, Dublin, and Edinburgh Philosophical

Magazine," vols, iv., v. " Clark," in Journal of Society of Arts. 1858." Hunfa Mining Records."

Whitney's Metallic Wealth of the United States." Kerrs "Handbuch der metallurgischen Hiittenkunde." Zippe's " Geschichte der Metalle." Von Cotta's Lehre von den Erzlagerstatten." Bodemann's Anleitung zur Probirkunst." Scheerer's Lehrbuch der Metallurgie." Plattner's Vorlesungen iiber Allgemeine Hiittenkunde." Plattner's Probirkunst mit dcm Lothrohre." Metallurgie du Cuivre par Rivot." " Le Play, Precedes Metallurgiques dans le pays Galles." Moissenet, sur le precede Anglais pour les Essais de Cuivre."

FRBiBBBa, Saxont, July ithf 1860.

Contents.

il Bketeh of Copper 1— 10

Atlta PbfBical and Cbemlrait properties of Copper . 10 — XJ g

b Blowpipe, ita occompaiijing instnmiBnts and re-agenta :

metiiod of aiing tbem to detect and detcniiiBe the

H of Copper and the minarala containing Copper as nu

lential oonslitnent 29_ Jl

le Geology, Mining, aud Preparation of the ores of Copiutr . 44 — 04

n Asntyiog, or the variona nieUmda uf eaUmating tbe per-

centage of Copper hi ores or other cnpreuua cumpouudB,

The Boslisb inothoil, the Gei-mui method, the AFisay wiUi

the Blovp'pe. The Humid Abbb;

1 Ute Natnre and Preparation of Pnela iWood, Charcoal,

Minoml Coal, Coke , 88—102

;eMttteriiJB; the Apparatos in which tlie rednutioii of Copper ia performed. The CteoenLl Princtptea uf tlie

Processes employed in the Metallurgy of Coppci' . . 102 — 117

ID of desDiiption, Metallurgie diviHion of ores 117 — ISl

tg of Copper ores in Wales — tie Kngliah ! . 121—148 g of Copper ores in Manafeld, in PruBBia- the

entAl method 146—172

ig of Native Copper at Detroit is the United Statea 1713 — 180 i Copper bytho "Wat Way," and varionfl other

180—101

ftHnB Kparation of ver and Copper , ... 101 — igg

ta &e Alloys of Copper 198-215

h Hm Working of Coppet and tlic MaLufaeturc of Cnpreena

prodBcU 215—228

lETALLUBGT OF COPPER

L CONBIDBltATlOSa BECAHDISa CorFER ; HlSTORT ; pBTBIDAb

I CSEUiaAL PnOPBRTIES; MCNERALOeiUAI. AND QHt>1.0I110A

Bblatioxs; Misma; Absatikq; Qeneiial 31etallubgi ; Vui

3 AFPABATOS aSED BT THE COFFER SNELIZR.

Chapter I.

ntaioBicAi Skbtoh of Copper.

of the I

1 COPPEK ia one of the six metals spoken of in

pid Testament, and one of the most important of the

Even mentioned by ancient historians. It was known

; as early as the time of Tural Cain, since lie

instructor of artificers in brass and iron.

historians relate that Cadmus discovered

, and taught its application to the wants of

liiud. It was found on the island of Euhtea, near

e town of Chalkis, and hence it has been assumed

Uie Grecian name Chalkos, by which the metal

town to Homer, Hesiod, and other ancient

I authors. The Romans knew copper as ae

t, and later as cuprum, names derived from that of

e island Cyprus, where Pliny declares the method of J

jjt was djscopered. It ia certain, that li-diiXVij

island the Phsnlcians had opened mines at a very eanjl date. Hence in the mystic nomenclature of the Alchfi mists copper came to be called Venus, to which goddeq Cyprus was sacred, and among their signs it was knows by the astronomical designation of that planet ?. TI English word copper, the French cuivre, and the GrnUI kupfer, were introduced into those languages durini the middle ages, and are plainly but alterations of i Latin name.

The mention of copper in the oldest records, B among the first metala whose use was known to mi kindj is consistent with what we would be led conclude, after a close consideration of its nature i the manner of its occurrence, Masses of the native metai, detached by water from their origiq bedSj and deposited in spots where a ivarHke went to seek stones from which to shape their weapons, by reason of their wejgiit, colour, lustre malleability, would quickly attract attention. Theil qualities, connected with the fact that the native maa are often of considerable size, render it more th probable that copper was the first metal upon whi were made the unskilled attempts of primeval smil and smelters.

In the Hebrew manuscripts no distinction is ms between pure copper and the alloy with tin, which modem times has been known as bronze, but which i our translations is rendered by the word brass. Th alloy, however, was undoubtedly the discovery of generation long posterior to that which made th earliest use of native coppei-, since tin uot being foum in the countries bordei-ing on the sliores of th< Mediterraneaa, could ouly have been introduced afteJ

THE METAIXtTBGy OF t

onmercial relations with distant European or Asiatic LS had been established. It is generally aasumcd, l&out any particular evidence to aupport the assump- n, that the ancients had a means of making this alloy tin and copper so hard that it wonld cut the most (fiactory rocks, and the existence of rast monuments 'syenite and porphyry are spoken of by antiquaries as Bxphcable under any other supposition. It is a fact provoking speculation, that the race of e Incas in Pern, although unable to reduce the iron Km that were scattered in abundance around them, td hence ignorant of the use of that metal, were well rare of the peculiarities of this hard alloy of copper Id tin, and forming it from proportions almost identical ifll those adopted by the ancients of tlic old world, ed it to construct the tools required for dressing the ones necessary in building their vast aqueducts and

The Israelites had bronze weapons in the time of tni. Homer represents his heroes fightin" with arms ide &om the same substance, and t f med an Iportant portion of many of the a' It 1 mple- its of the ancients. Bronze wa. a 1 n ed as

Uitterial adapted to the needs of th fin a t ; the ins of Rhodes, which was ou tn t 1 of this tsl, is a remarkable proof of the abimdance of copper mat that early date; and it is said that Mummius, ft the sacking of Corinth, filled Rome with bronze tttes, thus transporting Grecian art to the banks of t Tiber. Whether the Phcenicians who carried tin in Britain found tliere the knowledge of making use, is uncertain ; but it is a probable hypothesis, tbat I Snaticnl weapons and tools of hTowtd Souri \a,th6

TflE METALLURGY OP COPPER.

graves of some ancient race in various Europenn land and which archaeologists have determined to be Ctit remains, were obtained by the wandering trihea b<a& that region in Britain where at the present day tb| descendants of those same metallurgic Celts hare ma themselves the largest refiners of copper on tlie globe and in nhose vicinity occurs the ricliest and alnu the only known tin region within a circumferenc& inany thousands of miles.

The earlier money of the Romans was of bronze,.' more rarely of tlie alloy of copper with zinc, knows brass. Before the time of the Csesars no pure capf pieces appear to have been struck, and those of the tQ! of the emperors often show indications of having het silvered, by which process it is probable they were Hif to take the place of solid pieces of the more valnabl metal.

Descending into the middle ages, we find a new an important application of copper in its combination wit tin orJgiuiiting in the triumph of the Christian religia Church bells, which are made of this alloy, definitely mentioned in ecclesiastical records of H SQVonth century; they were brought into general n by Chiu'lcmagiie, and for several centuries were almo the only object for the employment of the founder's & In the construction and ornamenting of churcbi copper, bronze, and brass, liave played an importa part: the roof, the altars, and the sepulchral mon were often wrought of these substances; and th Ntntucs and decorations of pantheistic temples still exi in renovated forms in the worshipping places of Christ cndoni. The invention of gunpowder, and the snbael 9 UfUt jntrdduction of bronze cannon in the wars of thJ

The Metalutrgv Op Copper.

irteeuth and fifteenth centuries, had an import loence in increasing the value and the production of pper ; and as the civilisation of more modern periods r, the demand for a cheap metal, approaching in ita rties those of gohl and silver, increased rapidlv, til at present there ia scarcely a brancli of human Kiomy where copper is not found an important means RiriTiiig at greater perfection. Either unmixed oriu e form of a compound, it is employed in the con- tuction of nearly all kinds of machinery; for forming e delicate instruments of the astronomer, natural lllosopher, engineer, and musician; for increasing the airity of commercial enterprise by adding to the nbility of ships; as a path for the electric current in I bold journey from continent to continent in the s of civilisation. It furnishes a re-agent for the lemiat, and for the physician a remedy against disease. he sculptor employs it to express his conceptions, the ', aided by the engraver, to reproduce and dis- late his beautiful thoughts. The electro-metallur- uses it to catch and make prominent the evanescent 18 of nature and art. The glussmaker, the cook, the Fer, and those engaged in many other employments, latantly, while almost every advance made in i science adds to the number of its applications. 1 and Cyprus have already been mentioned as 1 known to the ancients for their mines of r-prodncing minerals. The Egyptians in early 3 drew their supply of the metal from Arabia, and ia related that one of the objects in view by Uamses 6 Great, in digging the canal across the isthmus of a, was to connect the copper-producing countries j Ptiie Arabian pem'nsula with liia Vmgdom oattva 5

Travellers of the present day find in the midst of tl waste, far removed from the region of fuel, remjuas I mines, and hieroglyphic inscriptions proving them i belong to an iige almost beyond the reach of history.

Upon the highlands of the Urals aud the Altai m found remains of mines dating from the most rema period, before the use of iron was introduced aa amatea for the construction of tools. The PhoEnicians brougl copper from Asia Minor, the Taui-us Mountau England, Portugal, and Spain, and during the nudd ages the last-mentioned countries produced a uot quantity of the metal under consideration.

At the present time copper is furnished from a n number of localities in every quarter of the globe. 13 United Kingdom however ranks before any oik country in the amount of ore raised and the we of metal reduced. The information we have regarda the early stages in the progress in Britain of botbti mining and mctallurgic divisions of this importa branch of industry, is remarkably scanty, and recca or traditions treating of the period prior to U beginning of the seventeenth century, are seldom at reliable character.

At Newlands, neai- Keswick in Cumberland, Boa rich mines of copper were ivrought about 1250, and would appear that in 1470 the place was still famoi for tlic metal it produced. Ecton Hill, iu Staftbrdshii was another spot wliere copper was obtained in coi eiderablc abundance, previous to the era of coppi tniniug in Com wail.

It is amusing, with our present knowledge of th mineral resources of England, to meet with Acts o Par]Janieut passed in the reigus of Henry VIII. an<

'W/B ETtix t) HS I bv cowan.

wwd VI. for preventing the esportation of brass Jj per, "lest there should not be metal enough left in Idagduoi fit for making guns and other engines of 1 for household ntensils ; " and even at so late date as 1708, to find a memorial presented to the vnae of Commona by the brass manufacturers, stating .t "England by reason of the incxhniiatiblc plenty of le, might bceome the staple of brass manufac- e for itself and foreign ports, and that the continuing a brass works of Eughind tvould occasion plenty qf igh copper to be brought in."

At tliis period the supply of copper came from the itinent, metal produced by the mines of the Hartz 1 Hungary was sold in the mngazincs of London, 3 indeed not until 1717 were Eugiiah pennies 1 English metal. At the end of the seventeenth y the attention of Cornish tin miners began to be ioosly drawn to the more valuable cupreous deposits them ; previous to that date, it is true, copper t had been sold a low price under the name of er, but this was produced by mines worked or iginally opened for tin. Tiic yellow copper pyrites the first ore recognised as valuable by the miner, B 6ir richer sulphide and black oxide of copper were ' a long time not considered worth preserving, and onsanda of pounds were cast into the sea or left mding in the lodes to surprise and debght sub- jBfint and wiser explorers. Deposits began to be i exclusively for the copper they contained, about e commcu cement of the last century, and from that to the present the produce of ore has gradually : steadily increased. The discovery of the rich i les ctf Angiesea ia 176S, the additiou of DevoflG

The Metaixubgy Of Coppeb,

shire and Ireland to the list of copper-prodiiciBi| regions, and of late years the immense importation ores from Chili, Cuba, and tlie Pacific islands, ban nrither destroyed the demand for Corniah ore i materially disturbed the law of growth.

The advantage of sending ore to be smelted iai rich repository of fuel in the Welsh coal basin ii very early perceived, and even in 15S6, according Carew, ore was shipped thence from Cornwall. 1765, several furuaces were in existence near Siutf and others along the coast toward the westward, general plan of the various processes then in appears to have been extremely similar to that jiractised at Swansea, and known as the EngtS method of smelting copper; and when we considerti complex nature of the numerous operations whicli includes, and the remarkable difference that exu between them and those practised at that time in i other copper-refining countries, we cannot but admi the ingenuity and judgment of those old metalli who, aided only by their clear powers of observat worked out a system which, while it is so excellent adapted to all the circumstances of the locality, caiv used in the treatment of every known variety of a and has withstood, with but changes, the keeni researches of modern science.

In the United States of America copper in Tiorkab quantities has been found in nearly all the Stat penetrated by the Appalachian chain of mountain The oldest incorporated mining company in the count appears to have been one for the purpose of worki; copper ores in Connecticut, the date of whose chi is 1709, Sut all other deposits at present sufficient

The Metallukgy Of Coppbk,

redoped to warrant a judgment regarding tlieir value ! exceeded by that tvhichj within the last sixteen M, Las been rc-opened upon the shores of Lake 5>erior. That this remarkable region was known to race existing at a period anterior to the earliest theaticated dates in aboriginal history, is evident fBi the remains which still exist of gangwaySj tools, d other proofs of skill which the races occupying the Bntry at the time of its discovery nowhere evinced, le Indians found by the first travellers were utterly norant of the methods of working that had been in s by the former race they bad no traditions to jlain the esistence of the numerous excavations, and lat copper they possessed was only such as they thered nmong the surface stones, The first record the deposit is found in the missionary report of the y of Jesuits for 1659-60. The savages bad then is utensils made from the metal, and huge blocks of e erected and worshipped among their gods. In "fiS, one Henry, a practical Englishman, explored the tatry at the imminent risk of his life, and in 1771 he sblished works, which were, however, soon abandoned, Che recent mining era of the region begins with b year 184'4, The explorations of various scientific I had made the region partially known to the dd, and miners drawn thither by the reports of L wealth, soon discovered large blocks of the er, containing much silver. A feverisli in among adventurers and capitalists, mpanies were formed in various parts of the 1 to work localities, of which, in many cases, not a. a survey bad been made. In 1847, the inevitable I, Bad of the hundreds of com-jame TiQisa.-

table I

10 THE HETALLTIBOY OF OOPfEB.

nally existing, only six were found actually eny mining. The distrust naturally resulting from ibh early disasters has gradually disappeared. The coil' vukion was beneficial in exposing the spurious and worthless schemes, and in pointing out those enter- prises whose inherent strength made them capable al weathering the storm. Since Ibat period the progreM of the region has been lieslthy, legitimate, and Uflr wavering.

Chapter 11.

f Oh the Pbtsical abb Chgmioal Propketim o

Copper differs from all other metals in possesi red colour ; its hue, however, is not to be confound with the deeper red, — known in common language n "copper-red" — that may often be seen on the sar&09 of copper vessels, and which results from a coating ol the suboxide. In thin leares, copper permits dii passage of light through it, and the colour transmittel is a beautiful green. Like many of the uncombinfl6 metals, it crystallises in cubes or octahedrons, whid forms are not uncommon in natural specimens, aii4 may he obtained hy precipitating the metal from solution by galvanic action. Its specific gravity, ol weight, compared with an equal bulk of water, varifl according to the manner in which it is treated,— thus : —

When east it lies betirDen S'BB and 8-90 VfhentammaredfcetwecnS-aa „ B'OO When in lie form of wires -73 „ 8-95 A piew cat from the oontae of a. tow ol nuti-so nif*al, 8'

THE METALLtTlQS OF COPPEB,

Iq regard to weight, therefore, it occupies a laition among the common metaU ; gold, lead, and Ter beiug heavier, and iron, tin, and zinc lighter. It Buperior to all the other common metals, except gold d wlver, in its midleability, or the facility with which allowa itself to be hammered into thin sheets, but Mde these, the two metals ii-on and nickel exceed it I ductility, or the property necessary for producing £wire. It ranks with gold and silver in hai-dness, I ionorous, and forms a part of some of the most Ukorous compounds with which we arc acquaiuted. fhen warmed, or rubbed, it gives off a disagreeable Biell, and its taste is faintly nauseous and metallic. lopper melts at a strong red heat, according to the Bcent determinations of Plattner at 2143° Falirenheit, t somewhat above tho melting-point of silver and 0, and when in a fluid condition appears of a sea- a colour. Upon being raised to a white heat it Dlatilises slightly, and combining with the osygen of t air, burua with a greenish flame. When pure t retains at all temperatures below the s melting-point, 'liigh degree of ductdity, and the harrlness and rittlmess which are produced in it by rolling and mering may be removed by heating. In tenacity, nest to iron; a wire '787 of a line iu diameter ataining a weight of 30Z'3 pounds. Its power of utdng heat is a little more than times that of I linear expansion, when heated from 32° to I O'O01879, and it ranks with silver above the s in its capacity for conducting electricity, aical symbol of copper is Cu, from the Lai The proportion with which it combii r elements indicates that its a\,Q\m(i

19 THE METALLURGr OF COPPEE.

31'71 times tliat of hydrogen; or wlieu ABSumed as 100, its equivalent number is 396-7.

Chemicftlly pure copper may be obtained by beatii tbe oxide in a glass tube, through which a stream hydrogen gas is passed ; the oxygen leaves the coppe and combines with the hydrogen, forming water, whit is carried off, and the pure metal in the form of powder remains behind. Copper which is precipitati from a pure solution, through electro- galvanic actioi by a means hereafter to be described, is also chemical pure. The "best selected copper" of the SwanU furnaces is almost absolutely pure ; the " toug copper" and the "tile copper" contain traces ' nrsenic, nickel, tin, iron, and sulphur, altogether, hoi ever, seldom amounting to more than O'OOS, or tha i one per cent. The Russian copper generally contai] some iron, although otherwise exceedingly pure ; tin from the native metal of Lake Superior is frequent very free from foreign substances, some analyses, hoi ever, show an admixture of as much as O'OOOS silva the South American commercial copper is often raiK with sci'npa of iron and the constituents of the ore.

By common temperatui-es copper remains in dry

" The folluwlag imnljaca show tha oomposition of seveial contiaej

fnimt])HaTti,iiDii]fse(lb}-Bodaman DSU „ BmdoB, nnalfiod bj Qutb . WK

mcliaiiged, but iu contact with moisture, or in tLc resence of acid vapours, it becomes coated with a green ale called verdigris. Upon the aliglit affinity, when inpared with other metals, possessed by copper for Eygen, rest some of the most important processes in 8 metallurgic treatment ; the following series, arranged I nearly as possible in the order of the strength of his affinity, shows how close, in this respect, it stands J the precious metals; 1, iron, 2. zinc, 3. lend, 4, shalt 5. nickel, 6. copper, 7. tin, 8. silver, 9. gold.

At a white heat copper decomposes water into ydrogen and osygen; the latter element then com- 8 with the metal and an oxide is produced. Weak nds, as for instance vinegar, have no influence on T except in the presence of air, hence there is no mger in cooking acid food iu vessels formed of it

orided they arc kept perfectly bright, since the tpoiu which passes off forms a complete protection Bin the suj'rounding atmosphere ; but it is dangerous bDow the food to cool in these vessels, because the it then gains admission and a soluble and poisonous IKlallic salt is quickly formed. In a state of fine don copper is a little dissolved by hydrochloric oflj while in larger masses this re-agent scarcely afi'ects

i Strong sulphuric aeid dissolves it when warm,

iwloping stifling fumes of sulphurous acid. But atric acid is its proper solvent ; by this re-agent it is educed at common temperatures, with development of opious red fumes of Lypoiiitrie acid, to a blue solution f the nitrate of copper.

Copper unites with most of the elements in various IDportions ; it will be appropriate here to describj

y the most important comliinatlQUB,

The Metaj-Luiwy Of Copper,

In combination with oxygen, Wbea copper is heittetli in the air it becomes gradually coated vith a red fibs of the sub-oxide, which passes graduidly into black or the protoxide. Both of theae compounds att moderately strong bases, that is to say they combJQf readily with acids forming aalta. The suboxide hi formula Chj O, and is composed of

lehotaft

It is found in nature beautifully crystallised in octahedrons, and is an important ore of the "When melted with quartz it gives to the resuldng compound a brilliant red hue, which resembles that efi the ruby.

The black or protoxide of copper has the formtdi Ca O, and is combined as follows :

79-85 parts otflopper, with SO'IG porta of oxjgsn.

It may be readily formed by heating nitrate c in the air ; when thus produced, it is a black pon which rapidly absorbs moisture from the atmosp} This is also a mineral from which copper is metal cally won, and it occasionally occurs in large masse

By the solution of this oxide in various adds, Beries of salts may be formed, all of which have, y containing water, a blue or green colour ; but whicU when they lose their water, become a dirty white. solution of any of these compounds may be rccognisedl by thefohowmg reactions : —

I Ammonia gives at a greeuish precipitate, but more of the re-ageut ia added, a deep blue colour ia poduced. Tlie ferrocyanide of potassium throws dovm L brownish red precipitate, which becomes reddish iqile irLeu the solution is very much diluted. Thia baction is so delicate that the smallest traces of a Uahle copper salt may be detected, when there is no at tlie same time preseot which renders the nriatic colour invisible, as for instance iron. A Hpote of iron or zinc, when dipped in a solution nalt of copper, becomes coated with the latter ntetal, which means of discovering its presence is very WTCnient and quite delicate.

K The most common of the copper salts are ; Sulphate m copper or copper vitriol, Cu O, SO + 5 HO. This nWgely used in the process of dying and in electro- W/tgy, aud is the substance from which nearly all chemical compounds of copper arc produced. in solution by the water flowing fiom many the metal is frequently reduced from it by to be described further forward. Carbonate WSa- or Malachite, Cu O, CO, + Cti O, HO, and Phrife, 2 Cu O, COj + Cu 0, HO, are found among He ores of copper, and are also manufactured by a Btffet process aud brought iuto trade as colours ; the Bift as "mineral green," the second as "mountain Hue;" hut both are liable to change their shade by Bunpoess or bad air. The compound of the oxide of Mppor with acetic and arsenic acids produces the

*fidiweinfuTt green " of commerce. It is one of the ; violent poisons, and is frequently used in the . lualacture of paper hangings,

I 3%f confound)) of copper with sulphnr. Mawi hS

comiuoii metals, when in a melted condition, coppo has the strongest disposition to unite with sulphur,

next to it comes iron, then io the order of tlidi attraction: tin, zinc, lead, silver, antimony, and arsenifl To tlie metallurgist this varying nfEnity is of tb utmost value in furnishing him a means of separating more or less completely, one member of tlie series fron another. Copper hums with a hriUiant light ffhel heated in the vapours of sulphur, producing the raS sulphide Cu S, which substance occurs in nature is known as copper glance. The compounds of coppB with sulphur are in their natural state generaH| mingled or combined with tlie sulphides of ii forming, as will he seen by a reference to the minas logical section of this treatise, the most important <aA of the former metal, I

The sulphide of copper, Cu S, is produced artiftcia™ by decomposing the oxide with sulphuretted hydrogeita it is a dark powder, which if left exposed to the ua rapidly absorbs oxygen.

"With chlorine and iodine copper unites in proptH tions analogous to those of the oxygen compounds. I

All the soluble salts of this metal are poisouoiM though in small doses they are occasionally admM istered as tonics, anti-spasmodics, or alteratives, b9 when taken in lar'ger quantities they occasion ifl flammation, and disorder the functions of the nervow system. The symptoms in cases of poisoning by coppd are, a cupreous taste, violent vomiting, cramps in thi legs and thighs, giddiness, convulsions, and insensij bility. The best antidote is albumen or white of egg J if administered in large quantities milk will answer tha tame purpose. The compounds known, as

aiETALLUBGY OP

Qied by the combination of copper irith one or n

other metallic elements, are 8o numerc

, and important, that a separate chapter j

de?otcd to a description of their preparat

band use.

CHAPTER m.

AccoupiKtrsa Ihsibdhebts abd RE-Aaar

1 DhTKCT, AMO DETBBliraB IHB JfATtTB*

r COPPiB Ores.

'na external characteristics of the substances which itinuaily demand the attention of the practical metal- in the form of ores, fluxes, slags, &c., are, in the jority of cases, entirely inadequate to euable him to ermine either their commercial value, or the pro- to which they may be the most profitably sub- tted. A knowledge of their chemical nature — of dr worthful or disadvantageous elements — is alone able of leading to this necessary information. ¥ew those connected with smelting have the time to to make themselves good chemists, since to such requires years devoted to tbis especial But the copper smelter has bis attention called but a limited number of substances, and compara- Sly to but a few processes, and hence the amount of anistry absolutely necessary for bim to understand baited.

By the labours of modern experimenters, an instra- nt has been perfected which seems to he the natu] utant of the metallurgist; since by it* .id,

without the possession of extended theoretical knoi ledge, lie is enabled to perform ou a small Bcale, atA while the substance acted upon is beneath his clon| observation, many of the same operations which business requires him to carry out, in hia furnaeea i smelting- pots.

This instrument is the blow-pipe, which, with essential accompaniments, furnishes the csperimentl with a powerful but delicate blast-furnace that J Tinder the most perfect owitrol, and ia capable, in very short time, with the aid of a few simple re-agert of proving the presence or absence of nearly every bU stance likely to be found among the constituents ores. The fact that the blow-pipe and its necessi , suite of instruments and re-agents are so easily til tained, and so compact, and that the ordinary studeij may gain (without the aid of a teacher} a considendd sldU in their use; and further that their application are so numerous, and the results obtained so worthy, that they are often capable of taking the pll4 of a complete chemical laboratory, — makes theif Bcription, and directions for their use, in a work this, especially appropriate.

The eiforta of Bergman, Bci'zeHus, Harkort, PlatMl and others, have gradually raised the blow-pipe fram'\ original position as a tjuman's tool to its present sat tific importance, and made it not only applicable to t discovery of the elementary constitution of compoud or to qualitative analysis, but have given it a high val as furnishing a means of executing certain quantilai analyses, or determining the amount of metal whit a given compound may hold. The metals that tiuB jirocess may be most accurately separated

r (W cotTBS.

I silver, gold, lead, copper, tin, bismuth, latA nickel.

[owing will be found a description of the appa-) (Te-agents, and methods necessary for discovering (Bture of those ores, slags, or mineral mixtures twill be likely to be brought to the attention of ppper smelter; and in Chapter VI. the qusnti- I method will be given, with suBcieiit detail to a careful workman to determine the amount of ait iu any given compound.

Iiption Of Apfabatus.

piiest form for a blow-pipe is that shown in thw ipitnying figure. It should cousist of a tube, a by bhes long, having at one end a k-piece of horn, f, shaped like the ity of a trumpet. At the other etube fits with a ground joint into fcder 6 c, which serves to retain the

eof the breath. Into this cylinder I tube, d e, is fitted in the same

; and to the end of this tube, by

1 ground joint is attached the pia-

point, e, of which a fall-sized lon-

mal section is given at ff. The

ng at A should have a diameter of 4

:. With the exception of the two

e entire instrument may be made hs or German silver.

The best instrument for supplying the required rfor blow-pipe use is that represented by fig. 2; tay aises of qualitative testing,

oy Ug. a ; I

Fia.2.

THE METALLtTtCT OF COPPER. '

ffa x, stearine, or tallow candle will i

The following dimensions for a blow-pipetl will be found <;oiiven fl Sin. ; c d;ij:in. 9 in, ; h, or the bn of the wick, i in. The of the lamp, a b, may jiipanned sheet-iron, remaining portions of instrument should b braas or German silver. portion A, which an: the purpose of a stand which small vessels mi placed to be trcatedj can be taken off when the lai otherwise in use. The wick shouhl be of cotton must be kept cleanly and evenly trimmed, . burning material, refined rape seed or olive oil mi used, or, what is still better, a mixture of one pi oil of turpentine with twelve parts of strong spii wine.

3. Beside this oil-lamp, a small alcohol lamj heating substances in glass tubes will be found n sary.

4. Platinum wires, about of a line in diameter inches long, used for holding substances while 1 melted with borax and other glass fluxes. They si be curved at one end into a loop, that the bead adheres to them may be more securely held.

5. Glass tubes closed at one end, abo\it ini diameter, and 3 inches long, and made of thin , that they may not break in the heat. These .ire to heat substances in, over the alcohol lamp, in ord

Rermiiie the presence of water, sulphur, arse r volatile elements. !. Glass tubes open at bolh ends, about i inch iu meter, and inches long, also made of thin glass, the purpose of observing the effects of the air upon ntances exposed in its prcaeuce to a high tempera- A bit of the substance to be tested must be [ iu the tube, which is then held at a slight angle h the horizon, and heated over the alcohol tamp. 7. Forceps of brass or German silver, with platinum iota, for holding splinters of a mineral iu the flame ule determining the colour produced by a high heat, i the smeltability.

. A small smooth block qfgieel and a small hammer, t proving the malleability of globules and breaking

'8. A number of pieces of well-burned homogeneous urcoal, made from fine-grained wood. 10. A small magnet, to test for iron, nickel, and Wt.

IL Beside the above, it will be found useful to s several and thin porcelain dishes, two or

J glass funnels, a smalt flask for holding water, a ooden stand for test tubes and one for filtering, and a

e or two of filter paper.

IHiese should be kept in small glass bottles with stoppers. . Soda (carbonate of soda} ; for reducing metallic lea to the condition of metals, TwsDce of sulphur and silica.

reducing metallic d I for dctermininfifl

The Metaultjesx Op Copper,

2. Neutral oxalate of potash fumislies a still dm ofiB-cient meaus of reducinf the metallic oxides.

3. Bora.T (biborate of soda) has tbe property' forming a transparent gluss, which becomes rarioudl coloured by the addition of different substances,

4. Sail of phosphorus (phosphate of soda and monia] is used in the same manner as boraii, but i produces a peculiar reaction. Nos. 3 and 4 are times called the glass fluxes.

6. Bisulphate of potash, for testing for the pi of boracic acid, chlorine, nitric acid, &c,

etre (nitrate of potash), for testing for

7. Nitrate of cobalt, in solution, for distingui between magnesia and alumina, and zinc and tin.

8. Pure lead, for the gold and silver assay,

9. finely-powdered bone ash, to be used for abw the oside of lead in the gold and silver assay,

10. Sulphuric acid, hydrochloric acid, nitric ticid,\

MANAGEMENX OF THE BLOWPTPE ANl

The student of blow-piping having possessed 1 of the apparatus aud re-agents that have been i tioned, is ready to begin his experiments. Hh I efforts must be addressed to learning to produce steady blast, aud to generate and distinguish betw the difl'erent sorts of flames. The operation of blovi should not be performed by means of the lungSj I with the inUBClea of the cheeks, the air is furnished 1 required to tlie cavity of the mouth, but breath ehoald pivcccd uudisturbed through the i

Iwne of the blow-pipe, possesses besides

of furniahing a very strong heat, tliat of acting' rerful chemical re-agent, and as such be chiefly studied,

t we examine the flame of a common we discover that it is composed of ts. At the base a small crescat a b dear blue colour ; higher up aud in tre of the flame, the dark conical e, surraandiog this is the luminous d, and exterior to the two last is the perceptible mantle /e. The student remark the nature of two of these s : the exterior non-luminous part/e, which is sd of giises already saturated with oxygen, that tertain circumstances goes over to bodies with be flame is brought in contact, and licence con- the oxidizing flame ; and secondly, the luminous d, which consists of gases not yet saturated

Lygen, aud therefore capable of extracting that

; from easily reducible oxides, and hence called

using flame.

a the point of the blow-pipe is held about one-

ff the breadth of the

1 the lamp flame, as in

I flame is produced by

that is long, slender> oe, is hottest at the ost point a, and is an ig flame. This action, t, ia strongest shghtiy

a, about il in the stream of heated gas. tie point of the blow-pipe be bdi a%

The Metau.Uboy Of Copper.

fig. 5, somewhat higher than before, and noSfl within the flame, i\. lai

more luminous c ing gases may be the direction c; witfaM bright portion of the S a, the above mentioned mtcHl action on oxides tu place, which causes thia to a called the reducing flame.

Examination Of Mixeral Compount

The student may now commence the examination the mineral substances, the composition of which I wishes to discover- In tliia examination it is usual ti pursue a regular course as follows : — Ist. Heating t! mineral in a closed glass tube such as is described ffl page 20, 2nd. Heating in au open tube, page 211 3rd. Trying in forceps before the oxidising flame I discover the colour of the light produced. 4th. He> ing the substance alone on coal to observe wlietherT| ia volatile, and what kind of a sublimate it forms, t ruoistening the subatance or sublimate with cobalt tion to bring out a characteristic colour. 5th. MelinI with boras and salt of phosphorus (glass fluxes) upo platinum wire, to observe the colours produced. Teats in the humid way with acids and other I agents.

During this course of cspcriments, pbc generally be observed which will decide the nature the Bubstancea present. The diatinguishiug eh(u ter'jstics in the beliaviouv of those metals or inctallofl

The MBTALLDRCit OF COPPER.

will be likely to be fotmii during the eiamiiiati jnerals contaiDing copper, or in tbc fluxes used|

metallurgic treatment are given briefly iu

owing list.

LVIOUa BEFORE TUE BLOWPIPE OF SUBSTATfCfl ILY TO BE MET WITH BY HIE COPPER SMBLI

, Sttlphur ; when heated iu an open glass tube, [taining sulphur generally give off fumes of sulpbl I acid, similar to those perceived wheu a cono] cb is lighted. If a substance coutaiuing sulphur melted with pure soda, and the mass brought uj BUI silver coin and moistened with water, a di t is formed.

, Selenium; when a small fragment of a mini taimng selenium is heated on charcoal, an odoi

nred similar to that of rotten horse-radish. . Phosphorus gives when the substance that

I it is moistened with sulphuric acid and held forceps, a green tinge to the flame. . Chlorine. By saturating a bead of salt of phoa- raa on a platinum wire with the oside of copper, then adding the mineral supposed to contain pine, in case of its presence a deep blue colour

be given to the flame.

. Fluorine. By heating a substance containing

: element in a glass tube with salt of phosphorus,

interior surface of the glass becomes etched or gbened.

. Silica {Quartz) when heated strongly with salt of Bphoms on a platinum wire, swims in a skeleton- I fragment in the bead.

phur

W TWe KKTaXXCMIT OF OOPPBB.

7. Aratmc in its vuiotta compounds gi'e a gatliql odonr, xnd & white Tapour when hratei) on cbwcotL I

8. Anlitaony gives upon charconl a trhite sublimaU but de?elopcs no odorous fames.

9. Copper gives with borax upon piatinum wire Ulfl in the oxidation flame a greenish bead, which M cooling beeomes blue : in the reducing flame this bew becomes red with the suboxide. "When its solutioafl acids is saturated with ammonia, a beautiful snd IM mistakeable deep blue colour is produced. fl

10. Bismuth givea on charcoal, a sublimate wbifl trhilc hot is dark orange-bellow, but when coollfl becomes citrou-yellow. fl

11. 7, when heated on charcoal, forms a wufl coating, which settles close around the assay, MM Todnces to metallic globules when treated with tifl reducing flame. With cobalt eolation this coaldH becomes bluish-green.

12. Letid forma a yellow coating on charcoal, wU in the reducing flame changes its place with the wH bition of a bluish .

18, Z'mc gives a yellow coating on coal, wldH npon cooling becomes white. When this coatingfl moistened with cobalt solution and heated in ttl oxidising flame, a yellowish green colour is produced/l

14, Nickel. In the oxidising flame and upon {Ih tinum wire, with boras, the compounds of this niBfl give a reddish brown bead ; with salt of phosphonirH yellow bead. The niekel reduces easily in the reducH flamOi giving these beads a grey colour. fl

16. Cobalt gives, with borax and salt of phosphgfl in the oxidising and reducing flames, a beautjH bJoe bead. J

Btaixdrgv op copper.

Jron. The compounds of this metnl give, npon platinum wire and in the oxidising fli

bot a reddish, when cold a yellow bead, which lecEucing flame becomes bottle-green. L Quicksikwr, when in combination, if heated p glass tube with osalate of soda, a grey metal ttDRtc collects in the upper portions of the glass. 1 Manganese gives, with borax, in the oxidisii An amethyst-red bead, which when heated in Utg flame beeomea colourless. , Alumina, when treated OD charcoal, moisten< cobalt solution and brought to a glowing heat, Biee blue.

, Soda, in any of its compouuda, gives the bloTi 9ittnB an iutcnse yellow colour. , Silver. This metal is beat sought for by meltii |>mpouud supposed to contain it — after roasting,

necessary — with test lead, and then bringing the lie produced, which will hold all the silver present,

a layer of bone ash. By a contiuual oxidising

the lead, may be oxidised and driven into the ash, pure silver that remains behind, in the form bright grain, may be proven by its malleability ith the hammer. This method of separating lead rilver is called cupelling.

Gold. To discover gold in combination with

metals, as copper, &c., the substance should be led; the globule obtained will be recognised by ilour and malleability. When however silver it in any quantity, the globule obtained will ' . In this case the silver may be dissolved out

add, and the gold will remain behind.

has been observed in a previous aect\on.,\\\a Vi\w

'4

TIIB MET-UiURGY OF COPPEB.

pipe famishes the moat genially applicable mi a metallurgist to discover the nature of those sul with whicli he deals. Without other aids it sufEcieut to settle the mineralogical species t his ores or their accompauimcitts may belong, all instances its nse dcvelopea characteristics essentially in classification.

Ores are often subjected to such fine me division before they reach the haud of the mets that simple atteutiou to their obscured physi perties will seldom lead to a trustworthy and conclusion regarding the interior nature of the i present. Crystallography must take a sub position in regard to its value for the determii species, since eveu where stamping has m resorted to, distinctly crystallised specimens of far from abundant, and with some varieties unkuottu. All the natural compounds of copper that are met with by the metallurgist, and with the e; several rare and doubtful species, and a few i that contain copper only as an occasional com all that are recognised by mineralogists, will t described in the following section.

Chapter Iv.

f or Comit, AND THE MniETUis ciiNTttniira Tiiit Mct

Copper uncomb'meii. nt Copper (Cu) generally occurs almost pure, !, filiform, and arborescent ; lustre metallic, and yellowiah-red. Hardnesa 95 to 3. Specific

8-8, ductile, malleable, streak shining, cleavage iptible, fracture rough; before the blow-pipe

fuses readily. Nitric acid diaaolvea it, giving off (ame time red fumes, and witli ammonia a lution is produced. Occurs frequently in Corn- ar Redruth and elsewhere; a mass of 122 pounds tained from Condorrow mine, Camborne. In

is sometimes found containing 7 or S per cent, IP. In the United States, near Lake Superior, rs aliundantly, and a mass was discovered in the iota mine which weighed 400 tons.

Copper in combination with Arsenic. eykite (3Cuj+2Ab), 71*7 percent, of copper i per cent, of arsenic ; occurs reniform dal ; hardness 3 to 3'3.; specific gravity 4-3

tin- white, sometimes bluish or dark, lustre c, streak shining. "When heated in a closed abe it gives off water, and forms a sublimate of IS ncid. B, B. fuses easily with an odour oi

toayeltomsh mass, witk soda ai\4 \iotot.

THE ItRTAl-LPHGT OF OOPTSB.

a globule of copper. This mineral is fuundin(3d and Cornwall.

Copper in combiitalion irish Selenium, Selenide of Copper (Cu,Se), 61'8 per cent, oioa Occurs in thin dendritic crusts ; soft;, lustre metal colour silver-white. B. B. gives tbe odour of sd and fuses to a grey bead j on coal, with soda, co] obtained. Occurs in the Hartz mountains.

Eucairite ([Cu, Ag] Se), 253 per cent, of co 43*1 per cent, of silver. This mineral is found or iu black metallic films, lustre metallic, and colj light lead, streak shining, S. B. acts as seleniJfl copper ; but by cupellation gives a globule of nh This is a rare mineral, from Sweden.

Copper in combination with Sulpkm Copper Glance, or Redrulhile (CUgS), copper 1 per ceut., aulphm- 20*2 per cent. Occurs masaive, pact, or graiiulai'. Hardness 25 to 3, specific g 5'5 to 5'S. Colour and streak dark lead-grey, am often tarnished, fracture conchoidal. Heated i open glass tube, gives a stroug odour of sulphui acid. B. B. on charcoal, melts easily to a globule, wIm boils and gives off sulphurous acid gas ; powdered C trcutcd with neutral oxalate of potash iu the redud llamu givea metallic copper. When quite pure ! Itklucnd may be cut with a knife aud melted in Hnmo of mi ordinary candle: the sulphide of iro&l oltuu pnitrnt iu it as au impurity, and this iuterl with titu linitliicti!! and fusibility of the mineral. CcsA null nlfiUiU Mili'iidid crystals in the Eotoi o? a. Mi-iSbSi!

kmbic prism, and it occurs there in veins mtb other M of copper. It is also found a.t f aGsnetbum, in iddingtonshire, in Ayrshire ; and Fair Island, Scot- td; iu Connecticut, Nova Scotia, aud Saxony. Variegaled Copper ore (3 CujS+FejS), 55-7 per nt, copper, 164 per cent, iron, and 281 poi- nt, salphiirj crystalliiies occasionally monometric, BOiular, lustre metallic, hardneas 3 to 4, gravity b to 5, colour copper-red to pinchbeck-brown, tar- ihed, streak greyish-black, fracture conchoidal and Even, brittle. When heated in an open tube, it Wa off sulphurous fumes, but forms no sublimate. B. on charcoal melts readily to a globule which is Bgaetic and brittle, and has a grey fractui-e; well anted it gives, with borax aud salt of phosphorus, the action of iron and copper. This mineral occurs th other copper ores in Cornwall, particularly at icroft and Dolcoath mines, where it is called by the wknaen " horseflesh ore." It is also found at Ross nd in Killarney, in Tuacany, and in Connecticut fCmUEjlvauia. Ago Copper (CuS), 66-5 per cent, of copper, '5 per cent, of sulphur j sometimes contains iron and id am impurities ; occurs massive, spheroidal, or as a iting, lustre resinous, cleavage complete, hardness I to 2, gravity 3-8, colour blue-black, streak lead- ly, thin leaves, flexible, erystailisation hexagonal, toa heated in an open tube gives off sulphurous ues, aud by high heat a sublimate of sulphur. "B. B. ma, after becoming red liot, with a blue flame, and ddaupon reduction a buttonof metallic copper. Occurs

tnally in Saxony, and abundantly in Chili, i

TimmiUe ([CuS + FeS]* AsSI, 40 to -"ta

33 The Metau-Ubgy Of Copper.

cent, of copper; loatre inetallic, faardneis 4'i, fracture uiieveD, cleavage imperfect, CTfstaJ monomctric. Heated in a closed glass tube gene decrepitates, and gives a sublimate of sulphur arsenous acid. B. B. on coal, melts with effervesc and sulphurous fumes to a dark grey magnetic glol After being well roasted, it gives with borax tht action of iron and copper. This mineral occurs number of places in Cornwall, but particularly St, Day and Redruth, in splendid crystals with o ores of copper; also in Norwtiy and Algeria,

Enargite (3Cu., AsS), 4S'2 per cent, copper, per cent, sulphur, and 19'1 per cent, arsenic; oc massive and granular, lustre metallic, hardnes gravity 4'*, colour iron-black, streak black, bri crystallises trimetric." Heated in a close tube enaj gives, after decrepitating, a sublimate of sulphur sulphide of arsenic, which is of a reddish yellow cci B. B. on coal, gives fumes of arsenous acid, osid antimony, and oxide of zinc, and in the reduction fl: with borax, yields a globule of copper. Occur large masses, at a height of 15,000 feet, on the Co leras of Peru.

Grey Co;*;)er {[Cu„S,reS,ZnS,AgS]'' [SbSIUS contains 30 to 40 per cent, of copper, and in f instances as much as lU per cent, of silver. Tes closely granular and compact, lustre metallic, i tallises monometrie, liardness 3 to I'S, specific gri 4-5 t'8 5'1, colour steel-grey to iron-black, st sometimes inclined to brown, but generally the ! as the colour, in thin splinters the mineral is si times cherry red, fracture uneven, brittle. Heate ised glass tube melts aometimea ittv ierac

n, auil gives with a very stroug heat r ilmk red llimate of tlie sulphide of nntimony. When the ore itions quicksilver, ns is sometimes the case, the iphide of that metal is sublimed at a low red heat, i collects on the glass in the form of a dark ring. B. on chavcoal melts ensily to a bead, gives oif much ,d covers the coal with the ivhite oxide of timony, and in some instauces irith the oxide of zinc lead. Allcr roasting and nieltiog on coal n itli soda, itallic copper may be obtained. The silver that may present is sought for by melting the roasted ore th lead and borax-glasa, and cupelliug. The Cornish near St, Austel afford excellent crystals of this ; also found in Freiberg in Saxony, Kremnitz in and the mines of North Carolina. Cupper Pyrites + Fe.,S,), copper 3i--Q per it., iron 30'9 percent., sulphur 34' 9 per cent.; occurs ssive or in dimetric crystals, lustre metallic, colour i8S-yeilow, hardness 3'5 — 4, specific gravity 4'1, often descent, streak greenish black, a little shining, aqun, fracture uneven, concboidsl. B. B. on charcoal, Lckens, but becomes red on cooling; raelts easily to a ibule, which is black, rough, and magnetic. Powdered d roasted on coal until all the sulphur is driven off, with borax and salt of phosphorus, the re- of copper and iron; dissolves in nitric acid, ming a green solution, which a drop of ammonia deep blue. This is the principal ore at the mes in Cornwall : it is there associated with the oxide tin, variegated copper, copper glance, grey copper,

and blende. The ore, when picked and reai sale, rarely yields 12 per cent, of copper, geuerallj 7 or S, and occasionally but 3 Qt 4. T\Xtf

LdyJ

may often be judged by its colour ; il' a iiiie yellow b and readily yielding to the bainmer, it may be sidered good, but if bard and pale yellow, it is jn from admixture witk irou pyrites. Copper pyiitM rendily distinguiabed from Iron pyrites, which it soa what resembles, by its inferior hardness ; it may bfl e with a kuife, while iron pyrites strikes fire with ate It differs from gold, for which it baa been mi by being brittle; hence it cauuot be cut ott' iu alil like that metal, and moreover gold is not attacked nitric acid. This ore is coinmou iu Sweden, in t llartE, in Tuscany, aud iu various parts of the Umt States, Canada, and Australia.

Copper Bismuth Glance (CujS + BSg), conf 18'9 per cent., generally in tbiu striated prisma, lul bright metallic, colour greyish or tin-white. In 1 open tube melts, gives off sulphui'ous fumes, TB forms a white sublimate of the sulphate of bismi with stronger lieat the specimen boils, and surroue itself with melted oxide of bismuth. B. B. fit easily, with intumescence, and gives with sodn globule of copper. This is a rare mineral from ( Black Forest.

Sulphide of Silver and Copper (Cu S + copperSl'l per cent,, silver 53'1 percent.; massive compact, lustre metallic, colour dark steel-grey, sti shining, fracture aubconchoidal. Heated in the o tube this mineral gives off sulphurous fumes, but uo sublimate. B. B, gives a copper aud sometimei, reason of impurities, an iron re-action; by cupellatioiv globule of silver may be obtained. Dissol' acid. The blue solution thus formed precipitates sili on an immersed copper plate. Occurs with iron

dlM

Siberia ; also iu Silesia, Cliili, aud Peru, auil ii tsr mines of Arizona. ri Pyrites (CuS [SnS,, Fc.S,]), copper 20-T cent., tiu 27'3 per ceut., irou 131 per cent. This lend occurs massive or in graius, its lustre is metallic, ittk black, colour steel-grey to irou-bluck, and has letimcs a bluisli tm-nish, fracture uneven. When Ged in an open tube it gives sulphurous fumes and a htsablimate of the oxide of tiu. B. E. on charcoal, or is expelled, aud aftenrards a dark scoriaceous rnle is obtained; the floal is coated vfith the 9xide of . With soda gives a globule of impure copper. At lel Rock, in the parish of St. Agues, Cornwall, this Oies accompanies iron pyrites and blende ; it is found fl granite of St, Michael's Mount, and in Sasouy. itUmonial Copper (CuS + SbS), with ai8 per it, of copper, crystallises in columnar prisms, lustre taOic, streak black, colour dark lead-grey, hardness gravity 1-7. When heated in an open tube giv§a off ,urous fumes aud vapor of antimony, which con- :a on the glass. B. B. on charcoal, decrepitates, readily, aud gives a subKmate of antimony; and a strong heat, with soda, a globule of copper, in the Harte, Oilman (CuS + FCjSt), 19 per cent, of copper; crystallised in cubes or massive, colour between i and brass-yellow, streak dark brown, liardness 4, gravity 4. B. B. fuses readily, giving off sul- fumcs, shows more irou, but otherwise re-acts Tflriegated copper. la found among the ores at Rneanao in Cuba.

%omvmuie (S [CuS, Pb] S + SbSa), with 18-8 ol copper, and 11 S per cent, oS Veatl.-, otxUTft

massive, gnvnular, or compact, crystallises trimetric,1o) metallic, liardness 25-3, gravity fj-S, colour and stn teel-greyor darker, brittle. In closed tube tlusspedl gives a dark red sublimate. B. B. on charcoal, ft easily giving off fumes of sulphur and antimony strong heat the charcoal ia covered with oxide of 1m In nitric acid dissolves, giving a blue solution. 11 mineral was first found at EdiUion, near Kedrnth; also occurs at Becralstou, in Devonshire, in Chill, i the Hartz, and in Saxony.

Aikinite (3 [Cu,,S PbS] + BiSJ, with 11 perceB of copper; occui's in slender trimetric crystals, massive, hardness 2, specific gravity 6'5, lustre mets colour blackish lead-grey or reddish, fracture une When heated in an open tube gives a white vapour ft sulphurous odour. B.B. on coal, melts easily, formil a yellowish white sublimate, and with soda reduces to metallic bead. Occurs in Siberia, and in the Vn .es at the Lubec mine in Maine.

Cuproplumbite (CuS, PbS), copper 19'9 per oe lead 65 per cent. ; occurs massive or granular, oi cleavable grains; lustre, metallic; hardness, S'j specific gravity, 6''i ; colour, dark lead-grey ; strei black; crystallises monometric. When heated in t open tube, fuses and gives off sulphurous fumes. B. on charcoal, gives a coating of the oxide of lead, affoid a metallic globule which, when melted with glass, gives copper.

Combinations of Coppei- tvith Chlorine. Atacamite (Cu CI 3 [CuO HO]), givi per cent, of copper; occurs in plates, massive, trimetric crystals ; lustre, adamantine ; hs dnes

THE AIETAIiLURGV OF COVPKB.

i specific gravity, 4'3 ; colour, various

;ht green, sometimes dark green ; streak, apple*

™, translucent. B. B. tinges the outer flame, when

ited alone, blue, and gives off fumes of hydrochloric On charcoal the copper is readily reduced to a

tallic state. Occurs in yarious parts of Chili, in Ih Australia, and in Sasony. It is ground 'der, and sold in Chili under the iiiimc of Arsei

and for drying letters.

Combination of Copper with Oxygen.

Berf Copper [CuO], with 8S-8 percent, of copper, Ts massive or granular, and in beautiful mono- ic crystals, sometimes earthy j lustre, adiimnntinc, tmietallic; liai-dness, 3'5 to 1; gravity, 6; colour, 1, of various shades, occasionally crimson by trans- Itted light; streak, brownish red and shining; frac- le, conchoidal and nneven. B. B, on charcoal, in e reducing flame gives a globule of copper; dissolves effervescence in nitric acid. Occurs finely crys- Hnel Gorland and other Cornish mines, in and New Jersey, and the Lake Superior and abundantly in South Australia. \ek Oxide of Copper [CuO], 79-S per cent, of '; generally occurs massive or. earthy; hardness, 3; ifio gravity, 2'5 ; lustre, dull; colour, dark steel- or black; streak, shining. B. B. yields readily the reducing flame a globule of copper. At Copper bour, on Lake Superior, 40,000 lbs. of this ore waU lOved from a vein in the conglomerate. It is alM id in the Ilartz, and in Sasony, and is abundant Burra Burra mine in South AustvaWa,.

98 TUB UeTjU.I.imGI OF OOffSR.*

copper, occurs in leaves, and possesses a ideKvage; lustre, metallic; barducas, 4-5; iH gravity, j ; colgur, dark -grey ; streak, browD. B. B. fuses vith difficulty ou the edgeH borax, gives a dull violet, aud with salt of greeu glitss. lu Lydrooliloric acid dissolves, fumes of chlorine, to a green solution. OccunH Thui'iugiaa forest.

Cupper in combination with Acids.

Sulphate of Copper {CuO, SOj + S HO), witli dl per cent, of copper, occurs amorphous or in tridin crystals; lustre, glassy; hardness, 8'5; gravity, S'lj colour, Berlin hlue to sky blue; streak, uncoloiue translucent ; taste, metallic ; somewhat brittle. closed tube swells, gives off water, and becomes nhits mixed with powdered coal, gives sulphurous ac fumes, B. B. on charcoal aud with soda gives metd copper. This mineral is fouud dissolved in water whi issues from mines, and in connection with rocks CO taining copper pyrites. It is produced in large qui titles in "Wicklow and Anglesea, also in Spain H Tennessee.

Brochanlite (CuO, SOj + 3 CuO, HO), with 66 p cent, of copper, massive, or columnar; hardness, 8'6 8pBci6c gravity, 3'8; lustre, vitreous; colour, doij green; streak, pale green, translucent. B. B, rediM with effervescence to a copper globule, which on coolb Ijecomes black. Occurs near Koaghten Gill in Oumbi land and in Mexico.

Linarile (PbO, SO, + CuO, HO), with 15-7 p cent, of copper is found in the form of wajsclinM

sometiinea an inch long; Uatrc, ritreous; [ness, 2-5 j specific gravity, 5-4 ; colour, deep azore i; Btreakj pale blue, translaceiit. In closed tube I off water, aud loaea ita colour, fi. B. reduces, vitli strou Leat gives a sublimate of oxide of lead- ore at Rougliten Gill and Leadhilla. nellite, probably a compouud of tlie sulphate and chloride of copper, crystallises in hexagonal prisms, t truncated edges ; lustre, yitreous ; colour, fine s, translucent; occurs associated with arsenate of JCT iu Cornwall.

*hotphochalciie ([CuO], PO + 3 HO), 56-4 per . of copper, occurs massive or indistinctly fibrous tfystallised trimetric; hardness, 4'5; specific gravity, J lustre, adamantine ; colour, dark emerald green ; green ; fracture uneven. In closed tube gives %ater, and becomes black. B. E. on coal melts dark vesicular globule, which contains a kernel of copper. With borax or salt of phosphorus, IB the reactiou of copper. Occurs at Virneberg on Rhine, and in North Carolina, *hophate of Copper ([CuO]% PO,, + IIO), with per cent, of copper, globular and compact ; crystals, Mtric; lustre, resinous; hardness, 4; specific gravity, i colour, olive green, translucent ; fracture, uneven, acts aa phosphochalcite. Occurs iu small quan- near Gunnislake Cornwall, and in Bolivia and

IcolUe ([CuO] PO,, + [U.O] % PO3 + 16 HO), itallises dimetric; cleavage, perfect; lustre, ada- and pearly, translucent ; colour, green; Bj specific gravity, 3'5; streak, green. to a black rnnea, colouring the ftame ?

TlIE BUiTAIJ.CRQV OF COPPER.

gives with borax a green glass, which becomes rede brown in tlie reduction flame ; in nitric acid fori yellowish green solution. Found at Gunnia lake, Croft, Huel Bnller, and elsewhere in Comivall ; alx Saxony and Belgium. ,

Malachite (2 CnO + CO + HO) contains 57-S, cent, of copper; usually occurs in globular for masaive or iucrusting; structure, radiating; ciyif monoclinic ; fibrous varieties, ailky ; colour, bri| green; hardness, 3'5 to -I; gi'avity, 3'7; streak, j green, translucent to opaque; fracture, uneven, glass tube yields water of a dark colour. B, B. on o fuses and affords a globule of copper ; with borax gii a green glass. Dissolves witb effervescence i and also in ammonia. Occurs in Cornwall and Cm berland, at Chessy in France, in the Ural Mounts! in large masses, abundantly in South Australia, various parts of the United States.

Amtrite (2 CuO, CO + CuO, HO), with 55-1 per of copper; massive, dull, and earthy; lustre, crystals, monoclinic ; hardness, 3-5 to 4 ; gravity, colour, various shades of azure blue ; streak, light bl translucent; fracture, conchoidal. B. B. acts as chite. Occurs at "Wheal Bnller, and at other plac4i Cornwall, at Chessy near Lyons in small quantitiei Alston Moor and in Pennsylvania.

Aurichalcile, a carbonate of the oxides of copper ainc, with 23'2 per cent, copper. Occurs in acii crystals, forming iucruatations, also granular; ness, 2 ; lustre, pearly ; colour, green, translucent, closed tube gives off water, and becomes black. B. with soda and borax on coal, gives a coating of oxide of zinc, and reduces to a globule of im

THE METALLPBCT t

;r. Occtirs at Matlock in Derbysfaire, at RougU and also in Hungary. }pAanesite ([CuO] AaO, + 3 HO), with 50 rf copper, and 30 per cent, arsenic acid, OCCt ve or radiated with perfect cleavage ; cryatals, idinic ; lustre, pearly ; colour, dark verdigris 1, to blue, tranalucent. B. B. deflagrates, molts ly, gives fumes of arseuic, and reduces to a metallic Occurs in Cornwall with other salts of copper, also in Sa\ony.

He ([Cud]', [AbOj, P0,J + HO), with 4M opper, occurs iu fibres, plates, or granular ;

ine, trimetric; lustre, adamantine, sometimes ly ; hardness, 3 ; specific gravity, 4-2 ; colour, olive irb green, also wood brown; translucent to opaque; tie, B.B. in tlie forceps colours the flame greenish, melts to a bead, which is brown and crystalline on .ng. On coal fuses, giving off arsenical fumes, to a le metallic globule, which on cooling becomes with red scoriie. Cryatals of this mineral occur |uartK at the Coruish mines, also at Alston Moor, !hUij and other places.

hteRroite ([CuO] ', AsO + 7 HO), crystallises letric, with striated faces ; lustre, vitreous ; colour, irald green; hardness, 3'5; specific gravity, 3*3; filucent fracture, uneven. In closed tube gives off Bt, and melts to a dark green mass. On coal melts detonation, and reduces to a globule of malleable Br. This is a I'arc mineral found in Hungary, Froth; Oxide of copper, 43'8 per cent., lie acid, 254 per cent., occurs usually foliated, Vlar, or massive; hardness, 1 — 2; gravity, 3; pearly J colour, greenish blue, tranaVuceiA.

m THE HETALLQSGT OP COPPKK.

closed tube gives off water, decrepitates, and gnu dark. On coal, melts, giving off arsenious vapours, reducing, with soda, to a metallic globule. Biaat in acids. Is found in Hungaiy, Saxony, and Sibedl

Erinile, ([CuO]S AsOj + 2 HO), o9-9 per I of the oxide of copper, 37"! per cent, arsenic acid, concentric crystalline groups, fibrous nnd rough, ti of cleavage; hardness, 4'5; specific gravity, 4; lo resinous ; colour, green ; streak, green, transltH Decrepitates when heated in a glass tube. On A coal, reduces, giving off an odour of arsenic, anS length a malleable globule of copper is forffl Erinite occurs associated with other arsentttM County Limerick, Ireland. '

lAroconite, 35 per cent, oxide of copper, with arM phosphoric acid and water, crystalline form, trimel rarely granular ; lustre, vitreous ; hardness, 2 ; spW gravity, 2*8 ; colour and streak, greenish blue, "V heated in a closed tube, loses water and becomes green. B. B. on charcoal melts with the developm of arsenical vapours to a elag. Dissolvea in nitric I without effervescence ; occurs, with various Ota copper pyrites, and quartz, at Huel Gorland and Hi Unity, in Cornwall, also in Hungary.

Chromate of Lead and Copper, (3 [CuO PbO] -A Cr O3), containing S'6 per cent, of copper. Is foul granular and amorphous, lustre adamantine, crystals form, monoelinic, colour, dark green to black, noq opaque; streak, greenish. B. B. on coal swells, inq with efi'ervescence to a dark green globule with sped of lead. With borax, in oxidising ilamc, gives a dil green glass, which in the reducing flame ia red. Tl mineral is found in Siberia, ¥rance, oai ISe-w XotV.

'muidate qf Copper, ([CuO, CaO] ', VO + HO), witU per ceitt. of copper, occurs duclv crystallised, va ii igonal form, also globulnr or as a coating ; lustre Y J LardneaSj 3 to 3-3 ; specific gravity, ; colour, It green or grey; streak, yellowiali green, trans- mit, lu a closed glass tube, wheu Iicatcd, off er and becomes black. B. B. on coal melts easily a slag which holds particles of metallic copper. Ih salt of phosphorus on platinum wire, gives a A which is yellow in oxidising flame and green in flame. Occurs in the Thuringian forest and Lake Superior region. did Copper, (3 CuO + 2 SiO + 3 HO) with per cent, of copper, crystallises rhombohedral, with cleavage j hardness, 5 ; specific gravity, 3'3 ; 5, vitreous ; streak, green ; colour, emerald green, ilucentj fi-acture, conchoidal. B. B. decrepitates, the flame yellowish green, and in the outer becomes black, in inner fiamc red, but does ;; fiises, with borax, to a green globule, and ia luced to metallic copper. Insoluble iu nitric soluble in hydrochloric acid. I'his beautiful found in Siberia and in Nassau. \Ua (3 CuO + 2 SiO, + C HO) with 35'7 of copper. Globular and massive, occurring lustre, vitreous or earthy ; hardness, 2 — 3 ; ivity, 2"1 i colour, green, passing into blue, — streak, white, translucent or opaque. as Emerald Copper. Pound, accompanying of copper, in Cornwall, also in Saxony, NoTB .li, South Australia, and Lake Superior.

Chapter V.

Qtotoat, Mixixs

IFiTH the exception of iron, the ores of no led extensively in the are more gei distributed thsin those of copper. Scarcely n pi division exists upon the earth's surface where tl not occur in workable quantities, A glance i Chapter devoted to statistics will show that, alt England, Chili, Cuba, and the Lake Superior re{ North America at present furnish most of the in commerce, the entire production is by no engrossed by these countries, as Spain, Austna fornia, and Peru may be said to engross the quid production, or as Cornwall, and Devon, and thi Indies almost do with tin.

Nor is the old theory that sought to estal relation between the occurrence of certain meta the position of the various zones of temperature,- placing copper, with iron, near the poles, and go. silver in the equatorial regions, — found to rest i general knowledge of facts. Copper veins pier formations that lie between the tropics aa abun as those that are cut by the polar circles. It w. of the metals mined in the dominions of the whose possessions extended across the equator, a ancient Indian term for the Andes is siiid to "copper mountains," while in Norway iVic UTe%

hat.

Ipolitan metal are wrought in the frigid regj id the INoitli Cape, tr is its occurrence con&ned to auy particular igical group. Each of the chief members of the a. which compose the solid earth-crust, at least as p as the chalk, have been found penetrated, more BB abuudautlj by its lodea, and it ia probable that, T certain circumstances, its deposition may still 5 forward.

iQ following table will furnish a rapid view of , as neai'ly as have been determined, of some of ; important copper deposits of the earth, and at same time will be found useful in giving the ili&hed succession of British formations, Although Ql be observed that in geological chronology no uive " age of copper " can be pointed out, yet it the time of the deposition of the Permian and B formations, the introduction of that metal among Toclcs, appears to have been much more extensive k during other periods. This age is represented in Jand by the Cornish deposits ; in Germany by the fertckiefer, and in America by what has been Dninated by some geologists, "the copper trap.''

THE HETALLTtBti)? COPPEB.

K>inM of Qrotipi.

LowJitjofCoppo-dapodl.

Benmt.

Snpirior.

Tsrti&ry.

Chalk.

IiAlgieraDeu-thaMoamtpM.. la Chili.

Wealden ud Oolite.

The Banat id Anatria.

Uos.

Dpurtcniest de rAFdjrroo.

Tfm.

Chessy in Fronoe. The depwiti of lAkt Superior, CoonECtieiit, New Jersey, m4 PennajlTanin, acoordiugto some aniliOTS.

Si

Permian.

fe!d xn Pmsaia, in Hesse, in Thnringi*. The copper Indea of ComwiJl thongh oi- oarriog in a much oUot rock.

DeTonian.

The Wea of WeitforJ, Irebn.l, at the eloM rf tSs or heginniDg nf following group.

Sikriui.

Esatem fkuk of the Ural inountainH,

Motiiniorpliic.

Alten, Korwny, and meet of the deposit* if Norway and Sweden. In the Alps, Ool- cabamha, Chili, and in Pern. ™

Ylrt METAI.I,UnOT OF coppeh.

Buiy circumstanoes connected with the oecurrenoB the ores of copper and other metals, arc beat explained by a reference to the theory which has heen devised iifter long observation, to explain the manner ich veins are formed.

c solid surface of the earth by an unequal cooling

I difierent parts; by the dissolving out and coD-

t sinking of limited portions; or by means of the

caused by earthquakes, has been rent by

r clefts or fissures whose length and depth arc

lite, but whose width seldom exceeds

I, and is generally only a few feet. Tliese cli

Dg deep into the earth and foruung

icted openings between strata of differept in-

1 or nature, natarally became passsgcx fur the

lation of water. Tiiis Quid at s high tcmfcrUtuns,

' the great pressure of the uipcriocumUjcnt

I, and while holding in solution carb/nic mtA nod

r chemically active substsaeei, w t/y (w

int, in one or another foriB, of sJi tlui

i in veins.

' irater aftei- filtering tbroujpb K;i'ul

f s rock holding even a xtry uusMte 'pwirlMr vt

ible metallic compound, would *- nt4wJAf

' I extent saturated with it,

-. where a circulation of

, would, upon receiving a i

a zone of lower pressure, or MHK iM

some new chemical compouud, itv\mifit fly

ince upon the walls of th i ffa .

the change happened to take place. This procesi going on for a long seriea of years would at length the crevice, and a mineral vein woidd be formed. That lodes are sometimes otherwise produced — as, for instance, by the condensation of vapom's issuing from a heated mass below, or by segregation from the surrounding rocktheic can be no doubt, but then are exceptions to the general rule of formation.

Mineral veins laiely occur singly The discovery d one in any district may be considered a good evidene* that others exist in tiie vicinity, for a convulsion general as an eiirth quake would natnraiJy produce numerous fissures, and their filliug would go simultaneously. But not only do veins form contem-' poraneous systems, but these systems are, as a rul similar throughout in the general character of ores, and aie composed of veins having a direction nearly parallel to each other. Further, it is founds' that frequently a vein, or a system of contemporaneora veins after having been completely formed, has been' rent by clefts running in another direction; and that these Bubsequentiy became filled with substancoft diflering in natm-e from those filling the first veinb This second system may be intersected by a third aai: of course younger formation, and so successivetf forward, the fact of cutting or being cut deciding tllB relative age of the vein or the system.

Observations made at the place of intersection of' various veins or lodes have often enabled geologists tff- fix the age of mineral deposits to be very different fronL that which at first sight would seem to be the case> Thus, although many of the Cornish odea are in granite, they have been proven to be the production

THE METALLCBGY Or COPPEH.

I a

riod far more recent than tlie formiition of tliat_ ; and by the following ingenious course of reaai

, for which we are indebted to Sir Charles Lyi Be been shown to be vastly younger than the coppi

ring lodes of Wexford in Ireland. Kn Cornwall the granite was first formed, then abi I same period the veins of fine-grained granite, ol penetrating both the outer crust of site and the adjoining fossiliferous or primary roi lading the coal measures; thirdly, elvans, holditi] straight through granite, grauitic veins, ( fossiliferoua slates ; fourtlily, I'eins of tin also taining copper, the first of the eight systems of 8 which have been traced in Cornwall. Here then. B the second system mentioned is already younger tl the coal measures, the fourth system must beloi still later epoch; and although the exact age lodes is difficult to detcrmiuGj it is quite clear] Jblished that they are not newer than the begiuuii Be Permian formation.

ow to turn to the Irish mining district. We hai Tdte in Wexford traversed by granitic veins which' I also intrude themselves into the Silurian strata, (same Silurian rocks, us well as the veins having I denuded before the Devoniau beds were super- fused. Next we find in the same country that ns, or straight dikes of porphyritic gi'anite, huvc hrough the granite and the veins above mentioned, Iiave not penetrated the Devonian rocks. Sub- tent to these elvans, veius of copper and lead were taced, being of a date certuinty later than t and older than the Devonian, for they do k tbe latter.

en, ger

so THE arETMXTTRST op COPPBR.

Thaa not only are the ages of the two series of i settled, but the remiu'kable conclusion nrrived at thai between the formation of the ores of Wexford and tlte ores of Cornwall inter\ened that immeuse period dtii which the old red sandatoiie and the coal measoiei were deposited.

By similar methods of reasoning, several of tl* conclnsions given in the last column of the foregMBg table have been arrived at.

Copper however is not always won from depoaik' such as have been described. It occasionally oc disseminated in workable quantities through limited beds of sandstone or shale, generally in the PermiaB rocks, as, for instance, in Manstield in Prussia, whae its ores are scattered through a thin bituminous laytf, known as the Zechstein, which has been traced far many miles. The peculiarity of these oi-ea renders H. expedient to adopt in their treatment a pecnliir metallurgic process, which will be found desoibai under its proper head.

It follows from the above general consideratins regarding the formation of veins, that no comprehoh sive rule cnn be given for the discovery of metalfie deposits. Especially is this the case where the esplorff finds himself in a country geologically unknown, and where as yet no evidences of mineral wealth have bc disclosed. Under such circumstances the discovery ii often due to chance, and the knowleilge of manyd the important mining districts of the world may bl traced within liistoric times to such a source : as fei instance the placers of California, and the silver, copper and lead region about Freiberg in Saxony.

But let a single vein bo found, and the search.

THE METAU.naGY OS t

ler Ttdiu asaumes a more systematic character; lugh even Lere infallible rules suited for every tiict arc impossible, and long experience accom- Bied by a soand judgment will lead to more valuable iults auy course reatiag entirely upon tbeo- dcal deductions. Blindly trusting exclusively to the e or tbe other of these methods of searching for itb, has led to the formation of many so-called rules bich are either local or false. A few however that founded on both, are worthy of the attention of y explorer.

Holes For Searching For Metallic Defositb.

1. Veins are found more abundantly in the older ystalline rocks, than in the newer stratified formations.

2. Veins are more abundant in mountainous and hilly gioBB than in the even land.

3. Metallic deposits are more abundant and richer . the vicinity of eruptive rocks, such as elvans or nnitic veins, than at a distance from them.

4. Veins may frequently be discovered by observing le peculiar form or coloui- which is displHved by the ir&ce of the land ; thus, in the copper region of Lake aperior, the miners are guided in their search for the ons of native metal by the narrow valleys which, in naefuence of the friable nature of the vein-stouc, vre been scooped out by the aition of water, above te Taluahle mineral. Circumstances of an opposite

icter exist in Algeria, where a lode containing gray ir accompanied by a refractory vein-stune of heavy

lar and spathic iron, traverses a soft marly formation.

lie easily decomposed enclosing rock has been carried J

ss

THE METAIXTTnOT tW COK*K

away by atmospheric agencies, and the veins rom&in liVe valla above the surface.

In uncultivated regions tbe fragments of the von are olten found scattered upon the surface, or colouriag the soil by their decomposition.

5. Springs issuing from the neighbourhood of metallic deposits often hold salts in solution, indicating the presence of certain ores,

6. The action of water in washing away the clay niid soil that hide the solid rock in which lodes occur, is of essential service to the explorer, and in many iustancea veins have been discovered by tracing the fragments of ore and vein-stone found in the bed of torrents back to the source from which the current had dislodged them,

The method of searching for mineral deposits M practised by the Cornish miners, ia called shading ot costeaning, and is applicable where the general direction of the veins is already known, or where the position of the vein to be sought is nearly ascertained. It carried out by sinking a number of shade pits eack about 3 feet in width, 6 feet in length, and having! depth sufficient to pierce the alluvial deposits and enter the subjacent rocks, in a line at right angles to the supposed direction of the lode. To avoid missing any trace of ore which may exist between these pits, they are joined at their lowest points by galleries cut throngh the rock, which give an opportunity for a more complete exploration. When the direction of the vein is not approximately known, this line of pits is crossed at right angles by a second line, and a second gallery ii driven, by which means, if any vein occur, it cannot fail to be detected.

The upper portions of many copper lodes,

cially those of Cornwall, consist of quartz, more or I fall of c&vities, and largely mised with earthy )wn iron-ore. Thia is called goBsan, and its dia- rery is hailed as the precuruor of wealth below, and ere the black oxide of copper is plentiful among the ruginoua matter, the abundance of copper-ores rther from the surface may be confidently exiiectcd. Before entering upon extenaivo preparations for mng, by erecting machinery or making large esca- ina, the vein which muy be discovered is thoroughly I by means of a small sunk through it, from lich the rubbish, ore or water may be drawn to the rface by a windlass worked by hand; or as the depth Ureases, by a whim or gin, which is a large vertical ndlass moved by horse-power; or where fuel is ondant and machinery readily obtained, by n port- le ateam -engine.

By this course the nature and quality of the ore may I determined, the amount of capital safe to devote to J enterprise calculated, and the dip or angle which e vein forma with the horizon observed. Should the vein prove promising, the miners' next s to fix upon some neighbouring valley from which gallery or adit level may be driven through the ontry to the vein, so as to secure drainage at as low a nnt as possible; a large shaft is sunk at a proper md supplied with the machinery necessary for swing up the ores and pumping out the water. The accompanying cut of the Levant Mine, St. Just, rich the daring Cornish miner has extended far Death the bed of the ocean, and whose steam-engine, rched on the cliff high above the surf, forms a iiuBg feature ia the bold coast scetieiVA .et'jc'ya

rni: metalldbgt dp ooppeh,

render more clear the conception tbat every metalll st should possess, of the circumstaDcee attending ti winning of those ores, the smelting of which is H immediate object of his care. It represents a sectid taken on a plane passing through the middle of thelodi The shafts a a, pierce the earth perpendicularly; i their mouths is placed the proper machinery for pni)i|

Id

a

ing the Tater and raising tht! ore that may be mine below Tlie gdlones or levels bbb, are driven tfartnq the lode neiilj in a horizoittul direction, and general at a distance of 10 fathoms from each other. The are large enough for the convenient passage of srai wagons, or otlier contrivances for transporting the O to the bottom of the shaft 'When not awtToiaft.eA. l

rock, thej- nre made secure by erecting aioond

I a stroog voodea framework, knowo as tiinbermg, lAi resists the outward {o-cssurc, and presents the

and roofs from caving in. These levels are joined ccc, which scrre as means of communication difierent parts of the mine, nnd furniab DnelB for the circulation of fresh air, wliit-U must be ried to every part of the works where men are jloyed. After the levels are driven, the ore is taken

of the space represented by the parallelograms by the operation known as sloping, and the open- thus formed is filled with the rubbish of the mine. I darkly shaded parts in the cut indicate tbe portions the lode which have been sloped, while the lightlgf_ ded facets designate the portions yet undisturbi

irbedfl

tXHBa OF EKTttiCTING THE OllE FKOM THE VEIN'.

[(Ht ores are so firm in their texture as to require employment of considerable force to loosen and ice them to fragments of a convenient size for ying to tbe surface. The method which is adopted ends on the [physical properties of (be I'ock, and the imstances that surround the mine. In Cornwall, he ground be passably soft, the ordinary pick and rel are found sufficient : if it be stratified, or filled I fissures, tbe miner has recourse to steel wedges or its called gd8, by driving which into the rook, he mabled to split off pieces of considerable size, ler and a far more potent aid in excavating is id in gunpowder, wliich was first introduced into [68 of Cornwall about the beginning of the IStli aiy. By menus of a steel clviaeV oy boTerViaVais

drilled a foot or more into the solid rock ; at the bottom of this hole n sufficient quantity of blasting' powder is placed, and a mass of soft schist — called tamping — is rammed very solidly into the remainder rf the hole, care being taken to retain a communicatioti with the powder by means of a sort of slow match, known as " patent safety fuse," or by a piece of wire which is subsequently pulled out, and fine powdw poured into the slender bole that it leaves. By meuu of one of these expedients, the workman is enabled to convey fire to, and explode the powder within the rod[, nnd a mass is thus torn away which is greater or lea according to the depth and direction of the hole, thB amount of powder and the nature of the rock. The mass thus dislodged is broken with hammers into small fragments, and the valuable portions picked out and sent to the surface.

A method of attacking the rock that was well koon. to the ancients, and that enabled them even with imperfect tools of copper or bronze to penetrate tie most refractory deposits, consists in exposing the ixxi to be excavated to the heat of a strong fire, until it reaches a high temperature, and then allowing it to cool. Unequal expansion, the action of vapours formed in the crevices, aud to some extent changes of a chemical nature, leave the exterior portions of the rock thus treated softened and full of cracks, so that it can be readily removed. This method, although stiil in use in a few mines where fuel can be obtained at a very low rate, as in some parts of Sweden and Norway and the Hartz, has been generally displaced by the intro- duction of gunpowder, nnd has now chiefly a historical iatereat.

[u extracting the native copper from the huge veini tlie Lake Superior region, a formidable obstacle is lerienced on acconnt of the vastness and solidity of musses in which the metal occurs. A hundred tons not unfrequcutly found in a single piece, which of rse before it can be drawn up, transported to the arc and shipped, must be divided into manageable Kiks ; these are now much larger than formerly, and netinies reach the weight of 8000 or 9000 Iba. The oal plan adopted is to dislodge the mass from the ill by heavy charges of powder, but this agent is adequate for accomplishing a further division, since I tamping, however excellent, is blown from the hole the same manner that a ball is driven from a cannon, mg slender steel chisels having a cutting edge about quarter of an inch in length are managed by two ine to direct the tool while the other strikes with lieavy hammer; by this means narrow channels are t, chip after chip, through the mass. The process, lich requires much skill, is at best exceedingly slow, irty months of constant work having been required cut up a single mass.

The ore of moat mines, when broken from its resting- ice in the earth and brought to the surface, consists two portions, viz., valuable metal chemically com- led with some mineraliser, as sulphur; and worthless n-stone or gangue that is mechanically mixed with rich portions, and which generally composes by far greater part of the mass raised. To separate this rthless gangue as completely aa possible, and thus icentrate the valuable metalliferous portions to ft Sioently high per centage of metal to make the thw concentration and purification. Vi ftte tofitblft

n seiies of merhanicsl processes wee in use, differing in vamns countries snd with varions ores.

In ComwHll the mineral upon arriviug at tbe smftes is thrown into the proper places appointed to receivB the various portions raised from the different piirtsof the mine; they are then broken or palled, and divided, into pieoea of good ore, commonly called prilk, dreigi ere, and halmva or Uav\ngx. The best ore reqairei fiuther preparation, but may at once be stored leaC for sale; the poorer, must undergo a process rf powdering, which is generally performed by machinay driven by water or steam. Two large cylinders fli rollers of stel or cast-iron are plnced close to ei other, and so geared together that they more in opposite directions. These rollers are turned lannd foreiblyj and the fragments of ore, placed in k above, are allowed to fall gradually between them 8ii4 are thus crushed to a coarse powder ; this powder tha falls into the interior of a long cylindrical sieve of wire- gauze, which is turned slowly by the same power moves the rollers. The fragments are thus divided iirtfl two clnsseSj that which passes through the meshes anil falls on the floor, and that which being larger than openings, is carried to the lower end there, falling ntt the buckets of an endless chain, it is elc-ated to Hat rollers to be re-crushed.

Instead of this apparatus for breaking ores tampiug-mill is sometimes employed, especially where (ho ores are finely disseminated through the quartz w vWwv hm-d niattei-s of the lodo. The atamping-miU* Ofiion by water or steam, and consist of a numlm WssiMrtSlil beams of wood or iron, having heads of HWHIC ft'C to 400 pounds at tl\e lowev eud. These

placed side by side ia n long trongli, tlie bottom of :cfa is of iron, and liaving to net the of an anvil, built on a deep and solid foundation. These stRmps capable of a vertical motion of about a foot, and SD in motion, arc alternately acted upon by a bori- itl axle conuectcd with the power and fiirnishod h cams that, coming in contact with enrs on the aki, raise them slowly and allow them to (all Ideoly on whatever may be beneath. The ore to he rdraed ia thrown into this trough, and coming under beavy hammers is soon finely divided, and may be away by a small stream of water that is kept itiaually flowing from one cud of the Icuugb to the

Mie ore is now ready to be subjected to A process concent ration, dieudiug on the different specific

fity of the valuable and worthless particles of the ler. As a general rule, the metalliferous parts that

as desirable to collect are much heavier tiian tliose it originate in the poor and earthy vein-stone. Thus

' a reference to the chapter on Copper Ores, it will be

ind that copper pyrites ia 4, and the sulphide of ipM" 5J times heavier than water; while quartz is ; 8J-, and chlorite but about 3 times heavier than the ae fluid. Hence it is easy to see how when a powder

Bidsting of a mixture of these Bubst.inces, is allowed to .through water, the metalliferous particles will reach I bottom first, and there form a distinct layer upon icb tie earthy particles will subsequently fall, or how, BQ such a powder is suspended in running water, the iter particles will be carried much further than the ivier, and may thus be separated.

The first of these principles is takeiv .4\OT,t,Aije i'

' 00

The Mk T Ax.T.'Uhqt Ofcofpeb.

the old method of washing ore by the hand-sierx. This is 11 sieve of couvenient size, having a bottom formed of a perforated sheet of copper. The workman partly fills it with crushed ore, and holding it in a large tub of water gives it a sort of undulatory motion which causes the water to enter at the bottom, and partly suspending the particles to be divided causes them tt arrange themselves according to their specific gravitiei. The fi'agraeuta lying on the top are considered worth* leas, and are scraped off and thrown away; the neit layer is put aside for further washing, while the bottom stratum is deemed sufficiently rich for metalluip: treatment. An apparatus requiring much less mani labour is now often used. It consists of a large h covered with a tight wooden floor, in the centre which is a circular metallic trough perforated holes each about two feet in diameter, and these openings a sieve is closely fitted. A large! working in a cylinder placed in the centre arrangement, and which is moved by an eseen is driven either by steam or water power, is alternately raise and depress the level of the the box, and consequently in the sieves which water-tight in the rings at the top of it. motion of the water the particles of the mini tained in the sieves are made to arrange 1 according to their several densities, and becomes necessary to remove a sieve for the purpose scraping off the lighter and less valuable portion of contents, its place is supplied by another, which is kept I ready filled to occupy the same ring when required. The contents of the sieve are then carefully divided, the lightest part thrown away, the poorer metallifero)

'Atj.Cbgy Of Coppek.

ps sent again to the stamping-mill, and the rioti ii the bottom put aside for the smelter. ( separatioti of different qualities of ore by meaoi tream of water, ia generally adopted wbere tha ing-mitl has brought the miueral to the form of a me powder. The apparatuses which have bef Ted for accomplishiug or aasistiDg this separatio Ferent mining regions, are numerous, and some> quite complicated.

! Nicking Buddie, often used iu Cornwall, conslati trough A B, furnished with an inclined head< C, over which a current of water may be allowed ffrom the bole e, the size of which is regulated bj den plug. At the lower end of the trough th) passes away through the holes at D. Thi Dg is performed by throwing powdered ore upoi; ;ad-board C, where it is stiired with a shovel unti washed into the body of the trough; here thi nan, standing in the huddle, continually swei broom the ore backward against the current l foils from the head-board. By this incessant

" 'natcd „„ , od la.™ "'' '"'Ml potl

„ '"o "Mara,., „ . '™' to the , " of the scllertl

J

Im wet is fised, so that when tine buyer and seller Pool, Truro, or BednitL, tlie biisiness necess&rjr nefcrring tlic possession of many thuusand poonr . of ore requires but a few minutes. The partu preaent a neutral persou is appoiotcd to the cbaiti.' gins by reading over the numbers and particulars lot to be sold, when each buyer writes on a slip of the price per ton be will give, and hands it to the lan, who examines the amounts aud declares the It bidder, purchaser. This Bale, from the manner iding' the bids in on paper tickets, ia called a. and the custom seems to have been mi nearly in its present form for about 1 30 yean.- ttly a sum called the gtandard was much used (at ting at once the rise or fall in the price of the It IB the coat of one ton of copper as reckoneel fling the price of that amount of metal as paid ore, to the sum of the cost of transportatii lag and the necessary profits. lier givea the following rules for fixing the price' ying ores ; — Ist, Fix the price you determine the contained in the ore shall yield ivlieu delivered works: say for example you lis union £65 pet' md the ore to be bid for has 14 per cent) !ply the percentage by the price and divide by 100.

14J- 91S -T- 100 9/. 3s. 7d. per ton of ore.

wre are 31 iundredweight given to tbe ton, ani general allowances amounting to 7 per cent. t(d Ided making 13s. Gd. + 91. 3s. Id. 9/. 175. li* Krom this sum ia now to be deducted the I ing charges, which are tbe net costs that practice hown are fnciirred in melting ru ove, KtA VVi

Her

:s

Ui!!.H

ars 'I rf le ,e

le

THB METAI:J>tnieT 01' COPPtR.

differs with differcut smelters, but for illustration will keep by the rule. An ore of 9 per cent, produce coats iis. per ton smelting; I. per ton is added fixf every per cent, above, and Is. deducted for every pw cent, below 9 per cent. Thus 14|- per cent, will cott 27. which deducted from 9/. 175. Id. leaves HI. 10s. lit as the sura to be bid for the ore. A little more or li is given according to requirement.

The next care of the smelting companies is to port their ore from the mines, to the various harboU of Cornwall and Devonshire, where it is gcirerally taken OD board as a return load by vessels that bring toA from the Welsh coal beds to supply the steam enntt and manufacturing eatabliahmenta along the southern coast, and thus it is carried at a low rate of freight to the wharves of Swansea or the neighbourhood, whenOft it readily reaches the furnaces. The vast quantitieac ore reaching Swansea from other parts of the world, crushed, sampled iu the same manner as is custosui in Cornwall, and sold at ticketiugs that generally place twice a month.

Chapter Vi.

' On AMitma ; on the viriods Hethodb of ElsTiHATiHa the fCKCUiiin OF CoppEtt IN Ores oh otube CnpfiKotra Cohtobiiiih. Thb SNdiaa Method. The Oeruin Hxtboc. Tbn AsaiT with teb Bmv- rm. Ta noaiB AsaiT.

At the commencement of all the raetallurgic pro- cesses which we are to consider, stand the following questions : —

st. What is the amount or percentnge of coppet tained in the ore or compoimd to be opernted

tnd. What is the nature, and what are the amounts }ie substances with which the copper is combined. [Jpon the replies received must depend the value of

ore or compound in regard to the amount of copper fiible to obtain from it, as welt as the character of

|m>cesaes that must be adopted to obtain the pure

tel.

estions so important as these require the moat tSvi consideration, and the office of the assayer, oie duty it is to answer them, is one of much ponsibility.

Phe art of assaying developed the science of Oytical chemistry ; it ia extremely ancient, and the s in use vary widely in different parts of the ibe. In copper assaying ive may distinguish four ierent modes of operation — iu the preliminary anination for all of which the use of the blowpipe, eChap. III.) is generally advisable, I, The English method. By this method most of the a of copper are assayed ; in some of the laboratories Cornwall it is employed to make from 8000 to OOO estimations in a single year. It is but an tation, upou a small scale, of the Welsh method of ilting and refining copper, which will be found Kted tit length in a subsequent Chapter, and con- oently by it the assayer obtains metal identical in litjf with that which he may expect to be produced the furnaces from similai' ore. Hence he ia ibled to determine, directly, the real value of the ore i the purpose of the smelter, for it ia vrsviexi 'CgsS*

TUB 3It:,TAI.t.DBGV OP OOPMSH.

VRliie is fts well tiD element of the quality as nl quantity of tbe metal produced.

Od account of its directness, the English metfai to be pi'ferred to all others, though, as regsxii accuracy with which the total quantity of copper tained in the ore, is determined, it falls behind t which follow.

II. The German method recommends itself bg simplicity, and the close approsiraatioa which attained to the full percentage of copper n ample.

UL The assay with tie blowpipe has the adM of considerable accuracy, and requires but little and but amall outlay for instruments ; but to at satisfactory results, more skill is necessary thai either of the foregoing methods.

IV. The humid methods of assaying have advantage of cheapness, ease, rapidity of execa and great accuracy, but for their proper raanftgemi moderate amount of scientific knowledge is i Several modificntious are specially ad.-ipted tOt determi nation of extremely small quantities of cop

r. THE ENGLISH METHOD OF ASSAYING.

For accomplishing this assay a wind furnace a such as is represented by the accompanying £ The openinsr, a, in which the fuel and crucible placed, is 10" long, 8" wide, and 14" deep to the bars, g. The opening, b, leading to the chimney, 8" long, and 2" high. The top of the openii should be furnished with a slide, which may be less drawn aside at the will ot tV\e .

Kming portions of the fumnce are Bnfficie:

bined by tlie figure. Good coke is used as fc

' tbe assay*, of which six

' be conducted at once, are

ed in crucibles and set

Dtly upon the glowing

jl; DO covers are used for

le crucibles, and tlie course

Kperiment can be obseirved

1 above.

I balance is required which,

t 450 grains in each pan,

turn perceptibly with the ition of j'g-th of a grain. i

he crucibles or smelting pots used are of Ij though but two of these are generally employem

iargest are about 4" liigli, and liave tlie ehie rn in fig. 9; the smallest will just fit inside the Bat. They are made extensively at Retfnith, and re |K>3ed of a light coloured, coarse, and very ictory clay. The outfit of tlie assaycr in- n OB, in addition, various tonga of cotn'enient e for handling the crucible while hot, rods etirring, mould plates for receiving the ed substance when poured from the cru- a bammer and anvil for testing the malleability le copper button, bronze or cast-iron mortars, and B8 or ladles of particulai- sizes for measuring fiuxes. lie fluxes and reagents required are, — common ta usual damp condition ; comiiion shM heating from moisture borax; powdered linu dcfed fluor spar; saltpetre; powdered chai r Bulpbar; and wAi/e/aa;, amixi.Mifc''ccwced.

the I&boratorr, consisting of tartar 3 volumes, sal Z volooies, and a small quautity of commoii salt ; are mixed intimately in a mortar, and deSaj before being uaed, by stirring witb hot iron r

Maimer of conductiny the assay of the ores of a by the English method.

A portion of ore which has been selected with care so as to represent, as nearly as possibly urerage richness of the heap, the value of whiohl be estimated, is brought, in a powdered state, i laboratory, and dried by a heat that should not e 212" Fahr.

A small portion of this powder is then plac shallow, flat-bottomed copper basin, and giving the vessel an oscillatory motion, and at t time allowing the water and earthy impurities t away at one side. By this means the different n particles are made to arrange themselves in according to their specific gravity, and a good j ment can be formed from their appearance, i general nature of the ore. Such judgment m mine the assayer whether to submit it to the t of the "warm sample," or that of the "raw samp]

The " warm sample " embraces the ores that c a considerable quantity of sulphur, and which i subjected to a preliminary roasting. The "raw si includes such as require sulphur to be added t or which are sufficiently desulphurised to n roasting. After the roasting of the minerals i first sort, which is done in a common crucibli requires from ten minutes to balf au V.o\w, t\M

bjected to the same general treatment ; th

]t stages of which are as follows :-

4. Fusion foi- Retptlus.

id. Roastiug the Regulus.

tl. Fusion for Crude copper.

%. One or two fusions nitli fluxes, called

" Washings." ;l. Testing witL the hammef and Hefining. ;h. Treatrncnt of t!ie slags for the copper they'9

contain for " Prill."

Fusion for Regvlua. 400 grains of the "ra " or the remainder of the same quantity of tl 1 sample " after roasting, are placed in one ( rge crucibles, and mixed with a ladle of each off ree fluxes, boras, fluor spar, and slaclied lime,! ffhich is added a layer of common salt, If tho'fl sample " consists of a very poor jtyrites, aafl nal ladle of saltpetre is given ; if the copper glance and other minerals containing 1 phur, i to 1 ladle of sulphur is adiied, so that t of this substance may be preaent to form egulus. These latter additions are made after fl Icible has been placed on the glowing coke, and J ined at a high heat for about 15 minutes, inutcs later a little lime, fluor spar, and borax I rown in, and at the end of about 20 minutea'f he commencement, the assay is poured out iuto-f vity of a cast-iron mould plate. The button T mned is taken from the iron plate and plunged 1 uter, where it must be allowed to remain after it I oled. This immei'sion enables the easy separa-a ' the sing from the enclosed vegiiluB,

TKB KBTAIXITBeT OP OOFFSBi

I the ftltove detailed process the object i Itorax 13 to form, with the quartz, oxide of ii THagnesia, lime, and other earthy subatances contail in the ore, the easily meltable boro-ailicates nh separate as slag. The floor spar forms volatile floor of silicunij and silicate of lime. The oxides of cop] antimony, tin, &c., lose their oxygen, attract aulpli and form a compound of sulphides which collect I compose the regulus.

This regulus should be bluish or bronze colont with much lustre, and containing from 40 to 70 ' cent, of copper. If it is either very poor and dul very rich and bi-ight, it should be rejected as being one case, too ferruginous, in the other as contun but a portion of the copper in the oi-iginal ore. 1 regulus is powdered finely in an iron or bronze mail a little coke being added to prevent adhering to sides of the vessel, and the powder poured carefi into one of the litrger crucibles.

2nd. Roasting the Regulua, The pot containing: powdered assay is now placed on the ilre. At first heat should be moderate that the particles may notbi together, but toward the end of the operation the may be iacreaaed. The assay is stirred coutinuaUyn a steel rod, and at the end of about half an hooi generally has assumed an earthy appeai'ance, and . more sulphurous fumes are evolved. The process, wh is simply that of driving off the sulphur, and form oxides of the mctala, is now considered concluded.

3rd. Fusion for crude copper. This takes place the crucible which has been used for roasting, ot ' of the same size. The assay is mixed with ladl< saltpetre) i ladle borax; ladle coal powder; 1 U

P THE jnCTSlXITROT OT COPPBB .

and 2 ladles of tartnr. Tno Indies i aitlt serve as a cover. At the end of ten stes iriien a good fire is maintained, tlie mass is |detdy fluid, and then a little white fiux is added, afternarda the crucible is removed from the loe; its contents poured by a single movement a greased iron mould -platCj and the crucible med to the fire. The object of this smelting is to m a crude copper, free from sulphur; the saltpetre to carry away the sulphor; the borax nets as a ; the salt renders the mass easily fusible. The powder and tartar are very important re-agents, I by furnishing carbonic oxide they reduce the 9 flf copper to a metallic state. th. Fusion with fluxes, " Washing. " The crude tr batton is now placed in the crucible together . orae ladle of white flux and two ladles of dry salt, white flux acts to oxidise the adulterating metals, the salt to form volatile chlorides with the arsenic antimony. After remaining four or five minutes fluid condition, the assay is poured out into a idd-plftte ; the button of copper examined, and if it very impure, it must be put through a similar of washing a second time. ith. Teglitiff with the hammer and refining. The cleaned of its slags is placed upon an anvil and id with a small hammer ; the presence of tin is icated by its hardness, of antimony by its brittle- It is then put alone into the crucible, subjected a high heat, and when it shows what the assayers I the eye — that is, clear bright edges and a peculiarly variegated centre — the same fluxes used ioJ are thrown in, and in a few minutes the flu)

73 TDK HftTAtiliTTHaT OF OOPPTia.

iDMS is poured it before into one of tlio moulil-pl In tlie midst of the slag is found the button of co possesaiug generally a clear red colour which u proof of the success of the aasny. If the fluxes thrown in have been aildcd too late, the batto found covered with a coating of the sub-oxide; if were added too soon the button is dull from unred oxides. The process of rcfiuiug is simply on oxidation i those metals which have more attractioi oxygen copper, as lead, iron, zinc, are acted i by the air, changed into oxides, which separate tl selves from tbe copper, causing the phenomenon of ei/e. The ores of Cornwall on account of their peci composition generally require a longer time before appearance of the eye, than those of foreign mines, Cth. Ti-eotment of the slags for the copper they con iMl slags from the fusion for coarse copper and I the washings have been carefully preserved. Thej melted with one ladle of tartar and some coal poi for about J of an hour. The globule obtained is " prill ; " it is larger oy smaller, as more or leas u has escaped into the slags. When necessary, i mbjected to pnriGcation, and is then added to copper button produced in the 5th process, and I are weighed. Tliis weight expressed in grains divided by i, gives dii-ectly the per centage of coj obtained from the ore.

If aa is mentioned in the description of the process, tin is detected by the hardness under Immer, and by the brown colour of the button, usayer will not be liiiely to obtain the eye satisfactc in the next process of refining. In this case, that tin may be eliminated as fidly as possible, the butto

mitted to one or more wasliings till tlie colour lleability of good metal are reached. 3ie antimony wliich ia also detected by the hammer, est driven out by a careful roasting. If washing is arted to a second time, a small addition of lead will

t the action.

Che presence of zinc is very disadvantageous, it is eeived by the regulus having a brown colour re- bling blende. A ladle of boras and half a ladle of ipetre will carry it over into the slag. !Jot withstanding the apparent complexity of the gliab method of assaying, it is capable in expe- nced bands of being quite rapidly carried through, 3 the nature of its different stages allows the detec- f the various adulterating metals with which the iper is combined. It gives invariably however too ]e metal, and to arrive at a figure representing the ftl amount of copper in the ore, it is necessary to 1 i to 3 per cent, to the results obtained. Hat the test — although it may want in scientific urncy — is adapted to the practical requirements of amerce, follows logically from tlie fact, that the loss the assay indicates and to a certain extent mea)

loss that must take place in the furnaces.

—The Oebman Method Of Assayino.

]

Bie process adopted for determining the per in mineral products at the varioiis smeltitig hhlisbments of Central Europe, differs considerably n the English method just described. It generally icates a larger percentage of copper iu the same , and it requires fewer manipulations.

opper iu the same i ions. fl

TBB HBTatLWBOT OF POPI

' In order to nccompUsh it, the foUowi Uid fluxes are required.

K muffie furnace, hnving the construction i the accompaDviag figure 10. It ia Adapted for soft or bitumiiK RU& in 30 arrani the emcibles do i in contact with or flames. It cc a mufBe a of ri clay with small t at the sides am end through w may , and aperture in fron may be closed wi iind which fum opening for int the assays. Th ia heated by bt strong 6re upon 1 flames of which play through the op rrounding n, and pass oft' by the chimni immodious ash-hole is supplied by the spa au iron door furnished with a slide g, ' the draught is regulated.

When coke, charcoal, or other flam is employed, this furnace ia replaced 1 constructed that the muffle liea imb the glowing mass.

2. Crucibles. These are made of and arc of an oval shape as repres Tliey are about 4i" high and I"

J

E:

The bottom, which is broken off aftor the

nble bas beea used, serves Tor a cover for subsequent

, in the manner shown at b,

Kiit. Roa*Hng cups, fig. 13, are also of fire-

f 1" Iiigb and 2" in greatest diameter.

L Tonga of iroa for handling crucibles.

It Eeaidea the borax, salt, and powdered charconl

1 is the English assay, powdered glass, metallie

fflic, lead, and grapliite are cmpioyed, and & misture

"black flus" is aa a reducing agent.

k consists of one part of saltpetre nnd two parts of

mde tartar, which after being intimately mLxetl in a

T are deflagr.ated by being heated in a crucible.

r ({f conducting the assa;/ of (fie ores of win method.

r and

tingnish here but three operationa. lasting, or depriving the ore of siilpbnr and Matile substances, and forming metallic oxi de. Y Melting for crude copper, ftefning.

tbt. Boasting. About 60 grains {:i-75 grammes) i

i dry ore are carefully weighed, mixed with about

i grains of graphite powder, and spread upon the

Mttom of the roasting-cup (lig. 12). This is intro-

l into the red-hot muffle, and a slight current of

f allowed to pass over it, until in about 10 or 15

mttea DO sulphurous fumes are given off from the

Bay. It is then taken out of the muffle, the powder

ihed carefully into a cast-iron or bronze mortar,

ind finely, and at the same time again mixed with

Bfi grains of graphite or coal-powder, and placed in thsJ

fire-clay cup. A second roasting similar to the first now accomplisbcd, and when no smell of sulplinroiU acid can be perceived upon stirriug, and the mass hfl an earthy appearance, which is generally the case ii 15 minutes, the assay is taken out and allowed to cvX

When lead or antimony is present, these roastinj , must be performed with great care, since by laim the heat too high, a partial melting ensues, and tb atmospheric oxygen ceases to penetrate the mass.

2nd. Melting for crude copper. The assay, after tfc process of roasting, holds the copper, lead, iron, i tin, &c., in the state of oxides, while the earthy purities remain to a great extent unchanged, Tb present melting is accomplished for the purpose turning as many as possible of the substances tilt besides the copper, compose the assay, into the slag, UJ at the same time to collect the partially purified coppe in a button. For this purpose borax and powdsrrt glass are the most active re-agents, forming a readflj fusible slag with the earthy impurities and most of the oxides ; and, when the proper proportions are present without acting materially upon the easily reducible copper, which, through the action of the black flui, gives up its oxygen, and by reason of its greater weigbft falls to the bottom of the vessel, and unites in a

A crucible having the form shown in fig. 11, is omI To charge it, the roasted assay is carefully removef from the fire-clay dish into a mortar, and mixed with 60 or 70 grains of black flux. This is poured into the crucible, and upon it are thrown, without mixing, 120 to 140 grains of black flux, then 3-1 to 30 grains of pawdereA glass, and 15 to 18 grains of borax. This a

THE ItETALLDBCT OF COPPIIB.

id by Ji layer of commoa salt (140 to 200 grarai

itly a piece of charcoal ' an inch square is I, For the purpose of forming a more fluid mass, asisting in the coDection of the copper, an nd<]iti< to 15 grains of metallic arsenic is made nith

and borax, when the ore is quite rich, and no It

seat.

c crucible ia now covered as shown in fig. 11,

d in the muffle. A red heat ia first given, whii

da the end of the operation is raised to whitCj ) or 40 minutes the smelting may be deemed com- The crucible is taken from the fire, and, after ng, is broken with a small liammer, and the copper, id with a number of impurities, is found in a welt- led button at the bottom. This button should

no dark crust of sulphides around it, and the rliich it ia inclosed should appear glassy and di n, without any disposition towards redness.

Refining. This process has for its object the fication of the coarse copper button, of aa many as ible of the various substances with which the last less has left it combined. It rests on the property essed by copper when in a melted condition, and Dsed to the action of heated air, of remaining

idised as long as iron, lead, arsenic, bismuth, mony, tin, zinc, nickel, and cobalt, are present. se metals are turned into oxides in such a case,

vhen borax is at hand, are taken up and carried aa a fusible slag.

te button is wrapped in a piece of paper with an h1 weight of borax, and placed with a pair of long I upon a cup of fire-clay (generally made by ing piece about 2" long and 1" WA'i.ft CKk.

IH THE HBTALLrBfiY OF COPPEE.

aide of a crucible, fig. 11), which haa already been in the muffle, and by surrouadug it with glowing c brought to n high red bent.

The button raclta in a few minutes ; and by opciAi the door of the muffle a stream of air is allowed to over the fluid. The osidcs of the alloyitig uietals f collect ou the surface, uud produce a play of colootl and at length the button, having lost much li impurity, becomes greenish, usually sinks beneath til borax, and, ou account of the higher smeltiug poinll copper, becomes solid. The cup is now taken from til muffle, and cooled by dipping it slowly into wiM The copper is found in a button among tbeslagjl should be well formed, bright, and malleable, and wl possessed of these qualities may be at once wi and the per centage of copper in the ore calculated.

III. ESTIMATION 01' COPPER JiEFORE THE BLOW-nV

This method, as I have before remarked, can oidy successfully earned out by a skilful hand, and all aome experience. But the fact that all the insti and re-agents necessary for determining the amooilt d copper in any of its compounds, may be packed in space not larger than an ordinary dressiug-case thus carried ou long and difficult journeys to commend it to a nation whose members may bl found measuring and estimating in all sections of Hi earth's surface.

In principle it does not widely difl'er from till common German method of assaj-ing, as just described The instruments and re-agents necessary to accompUll /i iave been spokeu of in Chaptei: Wl., ot "fliJi W

p in tiie course of the following dcscriptioii. Tb| hal sjatem of weights and meitsures Las lioc (ed account of their peculiar adaptation to t I of the experimenter in quautitative blow-pipin;;, J course of this assaj divides naturally into t

Ist. Roasling,

2nd. Meltiniffor CTvde copper.

."Jrd. Refining.

. Roatting. The ore, or product of the furuat it is to be assayed, finely powdered iu an agate| r, and, upon a balance wliich will turn wit) BilligrammG when loaded with % grammes, 1 deca-" pne is weighed with cure, aud mixed in a mortar

three times its weight of clinrcoal powder. The ftre is removed with a camel-hair peucil from the bir to a clay cup (shown in the drawiug), which iJcen washed internally with a watery solution of i oxide of iron.

, apparatus is now necessary, having the ., sLown in the accompanying drawing, i

80 THE METALLCaGY OF COPPEE.

fttrnished with the handle c, which may be mi screwing, to press against and hold the charcoal, a, h ita place, e is a roasting-cup of clay, 20 mm. in dia- meter, and 7 mm. deep, which rests within, and is hdd by a platinum ring that is fastened to the side of tia holder by means of the hooked ear /.

The mixture beiug placed, as described, in the cup e, the blow-pipe flame is directed through the opening d, at first gently, subsequently with more force till the cup ia raised to a red heat. "When any doubt remains that the sulphur is not entirely driven from the assay, more coal powder is added, and the heat continued. At the end of ten minutes the roasting is generally complete and the next operation may be proceeded with.

2nd. Reduction of the Metallic Oxides, or meiting, for a-ude copper. The roasted powder is removed firom the clay cup to an agate mortar and mixed with 100 to 150 milligrammes of dry soda; about 50 milligrs of boracic acid, and 30 to 50 milligrammes of pure lead. When the ore itself holds much lead the last! addition may be omitted, A strip of filter-paper, TvhidL' has been dipped in a solution of soda and dried, ia wrapped upon a piece of wood 7 millimetres in diameter, and a hollow cylinder of paper with one closed end thus formed.

The mixture is bmshed carefully from the mMti enclosed in this cylinder, and brought into an appro- priate hole in a firm piece of charcoal. The smelting is commenced by directing a reducing flame (see Ch&pi III) upon the assay, and continuing it till the maw becomes fluid and all the copper haa collected in a button at the bottom. This operation requires from 3 to 5 minutes, and after it ia CQuduieA. Wttan of

The Metallurgy Of

I latarae copper, whose principal impurity is lead, ia

broken from the slag by hammering it between paper.

1 3rii. Refinmff, The coarse copper button is not

Reimed before tiie blow-pipe with borax, as is the case

I the German assay. In place of this flux horacic

PHcid is used; this substance has the property of causing

(the lead to be readily oxidised and turned into slag.

L hole is made in the end of a piece of charcoal, and a

lantity of boracic acid equal in weight to the metallic

jatton is melted in it to a pearl. The button is then

Kid in the melted acid, aud first treated with a reducing

Bid afterwards with an oxidising flame ; the process is

mtinued till the lead lias absorbed oxygen and been

Jten into coinbiuation with the borax, aud the grain

f copper remaining asaiimea a greenish colour.

I The grain is now taken with a pair of foreeps from

B soft slag, and its purity proven by its malleability

beneath a hammer.

If the alag by its redness shows that some copper has been taken up, it is only necessary to direct a reducing flame upon it for some time, until the copper collects in a grain, from which the lead ia driven by I treating it with an oxidising flame. The grain of copper I thus obtained is placed with the larger one, and butb P are weighed; the expression of this weight in milli- grammes gives the per centage of copper in the sabstance assayed.

The refining operation requires about 10 loiuuteg, I the entire process of determiuiug the per centage copper in an ore by means of the blow-pipe, may be hnialied in from tiiree-quarters of an hour to an hour.

The Metallurgy Of

'. Thk Estimation Of Copper By The Humid 4

The complicity and partly the cost and inaci of the foregoing methods of estimating copper make k sometimes expedient to adopt the humid assay, fot which various processes are in use. The moat troU- woTthy of these are the following.

it. T7te Swedish met/cod. This is especially adapted for compounds containing little or no arsenic, antimoi, bismuth, or tin ; but even where these metals exist in the ore, results are generally obtained which equal in accuracy those by the methods described in the Bectiona I., II., and III. of this Chapter,

From 50 to 60 grains of the sample are weighed saA roasted in one of the fire-clay dishes, fig. 12, in the

mer detailed iu the description of the Grermiu method of assaying. When there is no doubt that

is composed entirely of the oxides and carbonates, this roasting may be dispensed with. The powder now placed iu a porcelain cup, and just covered wi concentrated hydrochloric acid. After this has been well stirred and evaporated nearly to dryness, strong sulphuric acid is added to the amount of about SO drops, or till the odour of hydrochloric acid is no longer perceived. The assay is again heated till the vapours of sulphuric acid begin to develop, when the dish is partly filled with water and kept warm for some time, in order that all the sulphate of copper that has been formed may be brought into solution. All the copper having been taken up, the solution is filtered in order to separate it from the earthy impurities that have collected at the bottom of the vesae\, vit\i Silwi

Tim METjU,I,rHGY OF Cori-EK.

ished witli warm vater until tke iluid posing tlii h no longer acid.

e zinc is then brought into the bluish lution, and by its electro- positive action the copper is wn down in the form of a powder, while at the 3 time an equivalent quantity of zine is dissolved i the bluish colour disappears. AVhcn all the copper 1 been precipitated, no red tinge will be given to n eof iron when dipped into the solution. By this Eople teat the time for removing the zinc may be bermined, and the remaining particles of that metal a picked out with a, pair of forceps, and washed care- Mly of all the copper tliat may have adiiered to them, The copper powder is now washed repeatedly with lldistilled water, until all the soluble salts have been VeoioTed, and then dried at a temperature of 213° and IPeighed. If no oxidation has taken placCj the weight haa obtained may at once be used for estimating the : oentago of copper in the ore ; but, aa has been wionsly remarked, this metal in the state of fine ision ia readily attacked by the air, and hence it is ter to change the powder at once into the oxide, by t:ng it for a few miuutes in an open dish, and subse- !BtIy weighing the compound. The amount of pure ipper is then obtained by the following proportion : 100 : 79'8 : : weight of oxide : weight of the copper I tiie assay.

, Then, the weight of ore originally taken : weight of I the assay : : 100 : the per ceutage of copper A the ore.

2nd. Pehuze's method of deter mining copper. This method rests upon t!ie fact, that from a solution of per to which an excess of ammomaVa.'s.XiceQ. wMsS.,

84 The Metallurgy Of Coppeh.

and thus the characteristic hlue colour produced, the copper may be entirely precipitated by the addition trf a solution of the sulphide of sodium, and as the la<t trace of copper falls, the blue colour disappears. It is evident, since the amount of copper precipitated must always be proportional to the amount of sulphide of sodium added, that, if we know the quantity of copper which each grain of the test-solution will throw down, and at the same time the number of grains we bare added of the solution, the quantity of copper in the second or aramouiacal solution may be calculated by s simple multiplication.

To detennine the number of grains added, it is only necessary to pour the fluid from an accurately gradoa- ted glass tube, each degree of which corresponds to & certain number of grains, and notice the positioii of the surface before and after the addition.

To determine the quantity of copper which each grain of the test-solution will throw down, a weighed portion, say one grain, of perfectly pure copper is dissolved in nitric acid, and ammonia added till a clear blue colour appears ; the test-solution is then poured in drop by drop from a graduated tube, till the blue coloui disappears, and the amount necessary to precipitate a grain of copper may be at once accurately read.

This amount being carefully noted, the experimenter is prepared to proceed with his assays. From 10 to 15 grains of the ore or other compound are weighed and dissolved in nitric acid or aqua regia (consisting of two parts of hydrochloric acid and one part of nitric acid) ; the solution is made clear blue by the addition of an excess of ammonia and heated to about 160". The BtandarA solution oE 5\j\5'\iV4e 'iVftTi.

3ded from a graduated tube, and from time to time le solution of copper stirred, and furnished with nmonia. At length the bine colour disappears, the amber of grains us6d of tlie standard solution are by observing the number of degrees through bich the solution in the graduated tube haa sunk, and the following proportions the quantity of copper

t is calculiited : — The quantity of test-solution necessary to throw own one grain of copper ; the quantity of test-solution sed : : 1 : the number of grains of copper present. Then : the number of grains of ore or compound riginally dissolved : the number of grains of copper : 100 : the per centage of copper in the ore or rannd.

Nomeroua determinations may be made with the e standard solution ; and since but one weighing is squired for each assay, and the remaining manipu- ODS are quickly performed, this method may be dTantageously used where a great number of estima- ions are to be made at the same time. Its accuracy 1 affected by the presence of cobalt, nickel, mercury. Bud silver, though the Iatte]|pnetal may be made harm- B by the addition of a few drops of hydrochloric acid. Methods similar in character to that of Pelouze have 1 proposed by Mohr and others, but none is at the tame time more simple and more satisfactory in its xesnlts.

An ingenious plan haa been used in Central Germany tnd also in Swansea for the determination of copper where the amount present does not exceed one pet i kt. of the substance to be examined, it rests uponjl ! depth of the shade of blue m ftie i

Ht\ TIIE METILLUBGY OF COPraMt.

solution above mentioned, which is compared with the shadea of a series of similar solutions, each containiag a known proportion of copper. To the one-thirtieth of one per cent, reliable estimations can be made by tha means.

Chapter Vii.

Oh IBS Haiuke asd Feefahaiion of Poku ; Wood, CuAMOAt) AtiNEBAL GojL, Cons.

Thk question of fuel with the metallurgist is one t£ primary importance. By far the mnjority of processes whieli he is obliged to carry out depend directly on the application of heat ; and upon the abundance and cost, as well as upon the nature of the materials that generate this heat, will depend largely the profit of has operations and the escellciice of his productions. "She position of the supply of fuel has as much to do witk fixing the location of the smelting works as the position of the metallic district, and indeed much more when the mineral reduced is rich in copper.

The copper blocks ofake Superior arc carried hundreds of miles to be smelted in the neighbourhood of the coal basins of Ohio and Pennsylvania ; while Swansea, situated in the immediate vicinity of abint- dance of coal, collects ores from every quarter of the globe. The wisdom evinced by the long established custom of sending Cornish ores to Wales to be reduced is clear, when we learn that, according to the old manner of smelting, it required 20 tons of coal to produce one ton of copper when the ore held 8 per cent. metal; hence, instead of taking 5.Q totva ot

THE METALUmOY OF COPI

I CoRiwall, 1 tons of ore were sent to Wales, Poor ores ff oopperoiitiiccoatrarj willaot pay for wide tranapor- pn : thus the smelter of the Unil gathers charcoal for t fornaccs from long distances ; and the copper schists ' Mansfeld in Prussia, are reduced near the minea, tlywith coke brought from England. The quantity 1 price of fuel further, to some extent, decide the Ukture of the process adopted ; thus, where coal ia very indant, the wastefiil but convenient revcrberatory nace is employed, as in Wales and in some parts of Bie United States. Where a less geuerous supply is band, the cupola furnace is often used ; and where still I can be obtained, the " wet way " is sometimea nnsidered the most profitable, as at Kio Tiuto in outhern Spain.

1 By Juels the metallnrgiat understands those com- nstible substances that can be used iu his processes T the production of hesit. By far the most important I taood, charcoal, vnneral coal aud coke, to whii Stoagfa holding a subordinate position, miiy be added brown coal and iurf, and the products of charring the same. The two first in the list arc natural products, aud are made up essentially of carbon, oxygen and hydrogeu, the second two are formed by art from the first, and are composed almost entirely of carbon, but in all more or less of other substances is invariably present, some of which remain after the combustion of the fuel, as the ask.

The process of burning consists essentially in the

combining of the carbon and the hydrogen o£ the fuel

with the oxygen of the fuel itself, and that of the atmos-

I pbere; the compounds produced vthen the process is

t, are principidly carbonic acid atvi waler.

been shown that the quantity of oxygen absorbed from the atmosphere by the combnstion of a fiiel which may be readily determined by what ia known Eerthier'i proceaa, may be taken as a measure of its heating powra. The following table, the result of the discovery of this lair and process, ia given by Scheerer, to show the relative amounts of heat produced by the complete burning (f equal voliunes of certain well known combustibles, pure carbon (diamond) being assumed as 100, the other iittiubera express percentages.

Pore carbon 100-00

Good mineral coal .,- 33-00

Olivooil 80-20

Alcohol 39-30

Dry wood 5-28

Charcoal *-B4

Wood, n-itli 20 per cent, moisture i'9i

Hjdrosen 0-0077

When a fuel is brought in connection with the atmosi phere to a glowing temperature, it bums either uittA Jlame — as is the case with wood, most kinds of mineral coal and compounds holding much hydrogen- without flame, as is generally the case with coke, char- coal and some varieties of mineral coal that are poor in hydrogen. The presence or absence of the qualities producing flame, has much weight in the choice of fuela for particular chemical operations, and influences essentially the form and dimensions of the fumncea in which such operations are carried out.

The Composition And Pkefaration Of Wood.

Although it lias been proved by repeated esperimenta that the corajjositionofrood is aVmost tVe iM&ft\\i.-8ll

[ Metallurgy Of Co

lecies of plants, yet ti great variety ia found to exist iu pect to the hardness, weight, ease of kindling, and Br of heating, which originates in the difference of cture displayed by dissimilar species. In general, reen wood contains from 37 to 48 per cent, of watery d or sup, which in the atmosphere does not entirely Sty out, since the best air dried wood continnes to hold rem 16 to 25 per cent, of moisture, known as hygro- c water. The ash of wood consists of potash, soda, me, magnesia, sesquioxide of iron, oxide of manganese, larhomc, phosphoric, silicic, and sulphuric acids, and lorine; its amount varies with the species of wood, ndwith the nature of the soil in which the plant grew, mt it is seldom under 0'5 or over 5'0 per cent. By the lying process the effective power of wood is largely ncreased, since thus the water is canied away that it otherwise be evaporated in the process of combns- , Hence the moat proper time for cutting this i of fuel is in early spring, that it may be piled to f during the summer. 'Wood may be preserved for a reat length of time either in dry air or under water, Dt when subjected alternately to the action of these ) it gradually absorbs oxygen, forms carbonic i , loses its firmness and rots, becoming worthless a fuel.

rFor some raetallurgic purposes wood must be dried at a high temperature in kilns, that the hygroscopic , moisture may be driven off as completely as possible. With such kiln-dried fuel when split into thin sticks, and placed on the grate in small quantities and frequently, the greatest amount and highest degree of t that can be obtained from wood, is secured. But paame firaejust enough air m\ist\ieai."[myjt\,ai.<Ma I

too much will cool down the furnace, and too little will allow the gases formed to pass off unburned. Hud woods hare all tlicir volatile combustible constituentt driven out soon after kiudliug, and a tliiclt coal remain! which gradually consumes without flame. Soft woods on the contrary usually give flame during the whole course of their burning, hence where operations are to be accomplished requiring this peculiarity, the soft wood should be preferred, and among these the pines furtiisb a wood rich in resins and producing tbe longest fl:i The copper smelter uses wood to kindle more solid in various processes, for roasting bis ores in fumaCM where an extensive flame is necessary, and when woridsg in the wet way to evaporate solutions in peculiar I(Hig reverberatory furnaces. Tbe operation oi poling, the stage in the process of refining by the Welsh method, ia performed by stirring the melted metal with long poll of green ash or oak.

On The Nature Of Charcoal,

When wood is exposed to a high temperature buoj the same time protected from the action of tbe air, it gives off various fixed gases, much water, several acid% and some tar. "When this operation, which ia callod dry distillation, is cai'ried on with rapidity, about 14 pet cent, of tbe weight of the wood remains as charooa) after all the volatile compounds have escaped. Wbu however tbe process is accomplished slowly, aa modi H 84 to 28 per cent, of charcoal is obtained from thesaioe wood. This remarkable difference originates in the peculiar decomposition that takes pbice when steam brought in contact witli hijj/Ui/ hx.aiv.d coal, a

THE METALl.rRtilf Ol' COPPKK"

of the solid carbon passing off in the (brm of rbonic oxide and carbonic acid gas. This is a fact of J utmost importance to the charcoal burner, who has lovered witiiout beiiig able to explain the reason, lat in order to obtaiu the largest quantity of coal, he inst perform his charring by allovping the beat to act nduaily, and never rise higher than can he avoided. Good charcoal retains the form and structure of the &om which it is made. It may he distinguished ita clear fracture, ghmcing bluish black surface and ! property of giving a ringing tone when struck, incompletely burned may he known by its lish appeLU-auce on the longitudinal fracture, and the duluess of the sound produced when it ia tnu. Charcoal possesses in a tresh condition the of ubsorbiug to the amount of 10 to li per tait. the gaes to which it may be exposed, and upon ya fact rests the phenomenon it occasionally exhibits spontaneous combustion ; the air being absorbed by Hie fine coal, and condensed in its pores, sets free taough latent heat to bring the mass to a glowing Although the weight of charcoal obtained by the usual methods of charring is generally not OTet IS per cent, of the wood used, yet in regard to volume t suffers a much smidler loss, bo that by properly con- acted processes it should afford GU to 70 per ceut, of original mass of wood. The object of charring rood is to obtain a larger amount of non-flaming com- itible matter within a given weight and bulk of fuel, facilitating transportation, and supplying the iceutrated heat required for many metallurgioj rations.

ON THE MANOFACTtrBE OF CUAKCOAL.

Charconl is produced on an extensive scale by methods.

1. By arranging the wood iu large piles, and covW ing it with a layer of loam or earth and thus hf allowing, after kindling, but a limited supply of air, securing a slow combustion of a portion of the woo which furnishes heat for the dry distillation of the remainder. This method includes the preparation IS. charcoal in mounds and piles.

The best time of year for this work is in summer or autumn, since then the weather is most regular, the days are longest, and the materials necessary for pa- forming it are easiest obtained. The mounds are formed by piling in a circular form, on a surface which hss been proven to he sufficiently dry and firm, from 15 to 25 cords of wood, covering it first with the charcoal dust or breeze obtained from a preceding operation, then with moss, leaves and similar materials, and pack' ing upon this an outer and more solid covering of earth. The wood is then kindled through an aperture that has been left for the purpose, and which is then tightly closed. The workman now carefully regulates the rapidity of the combustion by opening or closing boles admitting air to the burning mass. At the end of eight days for small mounds, and to sixteen days for large, the charring is generally complete. The fire is then smothered by piling sand and clay tight over it so that no air can gain admission. When 25 or 30 hours have elapsed the charcoal may be removed DOW ready for the ameUer'a \:i8e.

The Metaixcegt Op Copper.

, In regions rich iu wood, euch as occur in Sweden d Bussm, a system of charring inpika is usual. Loga to 12 feet iu length) and sometimes 12 inches in imeter, ai-e laid one over the other until a pile 20 to

feet long is formed; this is covered with layers of 1 and earth, as above described, and by a course not EFering much from that pursued iu charring in iiunds, a coal is obtained which is said to be of {lerior quahty. he gaseous and fluid constituents, of which wood

I a valuable store, are lost by the usual plan of larring iu mounds and piles. A third system is metimes adopted, where the valuable fluid aud luble elements are colleeted. For tliis purpose the ocess is conducted in permanent furnaces provided ith the proper apparatus to lead away and condense

s gases produced. The heat necessary to ehar the wd is either developed by the combustion of a

iion of the material in the furnace, or by a separate

I upon the exterior. The quantity of charcoal itained from ordinary wood by this process is occa-

lally 27 per cent, of the original weight, but at the

10 time 5 per cent, of the same amount is required

supply the requisite heat.

The copper smelters in some parts of the world are Dost entirely dependent upon charcoal for their ians of obtaining heat. In Wales its use is very lited, but in continental processes, it is employed Qtinually in the cupola furnaces, occasionally in the rerberatory furnaces, and as a fuel and re-agent in the ocess of refining it acts an important pai't.

THE METAIiLrBGT OF POPPER.

On The Nature Of Mine!

The fossil fuel dug from formations lower in geological series tlian the Tertiary, lias received the general name of Mineral coal. It is found chiefly layers or seams in what is known as the coal formatioi), but sometimes, and in limited quantities, in the strftti above and below that remarkable deposit. There are various sorts of mineral coal differing in their appeu- tnce and composition. It is sufficient for the metak lurgist to distinguish four classes that are foiuid(l' oo the behaviour of the mineral when exposed to Sn and therefore closely depend on its chemical compo- sition.

Caking Coal, upon being subjected to the action of beat sotteas, undergoes a sort of fusion, the yariom pieces adhere together and the original structure of tbs ooal is lost.

Sintei' Coal, has in a less degree the property caking in the fire, and by coking the original structOKI of the mass is not entirely destroyed.

iSanrf Coal, docs not cake on the fire, and when coluid does not agglomerate, as in the case of the two Ofiding divisions.

Anthracite, on account of the absence of volatila ingredients in its composition does not fuse vbn heated, and in many of its properties it approachea tlu coke made from other sorts of coal.

The following analysis made by various cliemiata will exhibit accurately the chemical differences that exist among the several classes : —

Kunerous experiments by Regnault show that each ftfonr dasseB mi\y be coisidered to have the foUawing ige composition anil specific gravity :

THE METATjLTIWJT OT OOPPKB.

. 85'81

, Newcastle B9'19

LsBquioke, GlamorgiuiBli. 91 '11

, SwansEa 02-16

PeiinaylTsnia 9t-89

Maoot OT-23

1-S5

Sand coal

Sinter cool .. Caking coal .. AnttiTacitc ..

Carhon. Hydiogei

%e amount of ash left by mineral coal after mplete combustion varies from 1 to 20 per cent, j ( average may be taken at 5 per cent., except lUiracite which contains, as a rule, still less. When spared with equal volumes of wood the lieating r of mineral coal may be generally reckoned as 5 1, and when compared with the same weight of wood 15 to 8, In order to obtain the greatest effect from 1 it must be divided into pieces of proper size, med on a grate of an extent proportionate to the rannt of ash produced, in a layer not too thick to ; complete combustion, and at the same time be supplied with sufficient air by means of a !n>Qey or blower. Miner.il eoal is used by the mctal- for roastinir the ore in heaps oc fattiaceai

smelting ia reverberatory furnaces and for boiling solutions. The softer varieties are not generally employed in cupola furnaces on account of their baking- together and forming a mass that is difficult for to penetrate. Anthracite, however, on account of its not possessing this property may often be used wifli good effect. The mineral coal of Wales is for tiw copper smelter of prime importance, since it forms s the large establislimeuts at Swansea the chief materia for producing heat. Two varieties are there diatiiiJ guished, a strong burning coal, and a iceak burnvt coal, which act very differently in the furnace. Thi strong coals have generally a large amount of volatJM matter and give a long hot flame; the coke formed during its combustion is light and spongy, and allow the air to pass free through it. The weak coals resemble anthracite in containing little volatile matt and hence giving an extremely short flame that scandf reaches the contents of the hearth, or they mayhai tk very large and diffuse flame that gives but little heab The strong coals are often used alone, but the weat must be mixed with the strong to secure a good result in the furnace. The composition of the ash of their coal is considered a subject of much importance by the furnace men, on account of its influence on a peculiar and very economical plan which they have devised for securing complete and effective combustion of all sizes of coal without the usual destruction of the iron grate bars upon which the fuel generally rests. This plan consists in allowing the ash to cake or clot together into cellular fragments called clinker, whicli collects in the bottom of the fireplace, and while pervious to the draught which it heata during its "jassajei forms

for tbe fire, and prevents mucli of the sva

&om being lost hj falling into the ash-pit.

On' The Nature Of Coke.

r many purposes the metallurgist requires a fuel is devoid of those constituents which ukelt and at a low temperature, thus diffusing the heat producing a clotting which prevents the air for combustion from properly penetrating .burning mass. Such constituents which are more leas abundant in mineral coal, are separated by a Bess known as cokiny, in the course of which the ihur that also exists in most coals and for many lurgic uses is very disadvantageous, is partly en off. Anthracite which is itself a sort of natural i, is not adapted for this process, but the other three EtieB of mineral eoal with the properties of which student ia ah-eady acquainted, may be submitted twith more or less profit, and the coke producei igh differing according to the nature of the ( ihyaical qualities, is when considered chemically similar.

Good coke oonsiata of 85 to 93 per cent, of carbon

le is not essentially different in compositi that in the coal from which it is made, but it- i tys found in a larger proportion ; thus coke having to 12 per cent, ash is made from a coa! with but 5 per cent. The water which it attracts, like char- . from the air, may amount occaaionally to 20 per . Compared with an equal wei£\it o? "jxuft ttitW,

99 THE KETAtt-tHtGtT OT -CdWEE.

coke gives '85 to -Qa as much heat. Caidug coi i produces a poroua, iron grey coke with a silky, a sometiraca almost metRllic glauce, and in the pioceaa ( coking it melts, forms a doughy mass, and, on nccQiU of the numerous bubbles that are formed withiaJ increasea considerably in volume. Sinter and i coal, not melting together, remain nearly unchangB in form and volume, when subjected to tlie i influences. The specific gravity of the three sorta coke, and their heating power, when compared i equal volumea of pure carbon, are, according ' Scheerer, as follows : —

Spe. GniT. Specific Ueai.

On The Manufacture Of Coke.

! is the ease with wood, so with mineral coal,- rapid driving off of the volatile ingredients produce* I loss which may be prevented by gradual beatiDgj I (act the process of coking is, in moat respects, aim to that of charring, and the general principlea of apply to the other.

Like charcoal, coke is made by three methods : mounds, in piles, or in furnaces. By the first 1 methods coal ia generally used which has not been reduced to very small fragments, by the last, powdered coal ia also brought to the condition of coke.

Coking in mounds and piles. This is done, when tl coal is in sufEciently large pieces, by building, in th( centre of a dry sandy spot, a simple brick chimney, S or 4 feet high, furoished with numerous apertnru 1

htALLVtaOY OF onrPER.

Irer end, and with an iron plate capable of closinj per opening. Radiating from the chitiine as B, six or eight small canaU are built of large pieces al or of bricks ]id closely together to furnish ge for the air. Upon and around these canals >al is heaped in a circle, 18 to 20 feet in diameter, [urying gradually to the chimney, wliere it is 3 to et high. A coating of damp, powdered coal, or e, about 3 inches thick is laid evenly on the se, and fire is started in the central part, and Ed to estend itself gradually toward the periphery, le end of 48 or 50 hours, vapours and smoke cease (ue from the chimney, the coking is considered ilete, and further combustion is prevented by (g all apertures that can admit air to the interii e heap. The fire is thus smothered, and le coke has cooled it may be drawn and is readyl ae. In coking in pUes the process is essentially tetme as that described ; the most important BDce being in the amount that is thus manu- red together. The form of the piles is generally Bgniar, 10 to 12 feet wide, and 100 to 150 feet When it is necessary to coke powdered coal by means it is moistened so as to adhere slightly her, and budt in narrow heaps around smootli of light wood; after the piles have been fully id and pressed down, the logs are carefully drawa' caving numerous holes for the passage of air. It., en covered with a layer of breeze, set ou fire, ai ed to burn until fully coked, when it is quenchi rcnching it with water. jKuff in furnaces. Coal " small " is more conve- ly eoked in furnaces than in lien.\ia, aud in some

localities coal is powdered by machinery before subi jecting it to tlie fire, that a more homogeneous coU may be produced. The furnaces may either be opel or closed. The open, or "field" furnaces consist a four simple walls, about 4 feet high, enclosing a reel angular apace about 8 feet broad and 100 or SOO fn long. The side walls are furnished with apertnil through which smooth logs are tlirust. The coal i packed into the space between the walls, fumisha with a cover of 6ree-e or loam, and after the logs hav been drawn out, thus leaving the mass penetrated will air-canals, kindled and allowed to bum for 8 or 9 daj) when the process is generally completed.

The number of closed furnaces that have been pM posed and tried for making coke ia very large, and who the demand for tliis species of fuel is extensive, one ( another of these contrivances generally takes the pliil of the heap, or open furnace plan. According to theoldi systems these furnaces are constructed in the form (J an oval or circular vault, with an opening at the to|6 through whicli the coal is thrown, tliat can also answo: the purpose of a chimney, and a door at one side froOt which the coke is drawn by hand. This plan has, nf many places, been superseded by furnaces constructed like long vaults about 3 feet broad, 4J feet high, and 25 feet long, which are built side by side, forming n long row. Two holes in the crown of the arch of each furnace serve to charge this furnace with coal which, after being spread evenly along the vault, kindles by the heat of the glowing mass in the neighbouring furnace. Through small holes in the wall the work< men observe the progress of combustion within; when, at Jength, a red glow takes the place of li§]

METALLUaGT i

d or bluish flames, the process is considered led; the large doors at each end of the vault Dcd, and, by means of a huge pusher, worked by ! steam-power, the entire mass is slowly slioved ) the cooling yard, where it is quenched a ae time, dispossessed of the greater part of its ", by throwing water upon it. The amount, by obtained from the different yarieties of coal !8, according to Scheerer, for

Sitnd coal. &om 55 bj 65 per cen

Sinter omI 60 „ 70 „

Coking coal,., „ 60,, 60 „

coke produced in furnaces is solider than ,ade in mounds or piles, and weighs about S'

more per cubic foot, 1 coke may be known by its homogt E presence of no fragments of slate ; by solidity property of withstanding pressure, a clear bright

and a small per-centnge of ash and sulphi e copper smelter, coke is capable of taking the )f charcoal in most cases; he uses it when as, unmeltable, and highly concentrated fuel i' id, as in the cupola furnace. Much more rarely aployed for roasting in heaps, but, on account of ducing little or no flame, it is not adapted ve use in the reverberatory furnaces.

The Metallorgt Of Copper.

CHAPTEa vni.

Or Fdrnaoe Mitehiils; OP Ci

ON THE MATERIALS USED IN THE CONSTRUCTION I FURNACEa.

TuE durability of a furnace depends essentially upo the nature of the materials from which it is constructed No Bubstauce with which we are acquainted is capabid of completely withstiinding the action which must g forward in the interior of a smelting furnace, tl frequent changes of temperature, the intense heat necessary to melt refractory ores, and the dissolving power of the gasea and fluids that arc tliere prodiicedr The compound of silica and alumina known as fire-cli possesses in a higher degree than any other common substance the properties necessary to enable it to. resist the effects of these destructive agencies, and it i! generally employed for forming the lining of furuacei, and the coostruction of such parts of metallui- apparatus as are directly exposed to the action of intense fire. This material is usually moulded into bricks of the common shape, or into blocks adapted to particular parts of the furnace to be constructed, and baked firmly, before coming into the bands of the metallurgist J and since all clays on account of a loss of combined water, or a partial fusing together, I decrease in volume or crack Yiteu euswi.

' TUfi ttETAtXTtHCTf OF COPPER.

il state to a high heat ; all good fire-bricks

partly from clay, that previous to its bein| led is strongly ctilcincd and reduced to a powder, 1 English clay has long held a high place in in of European smelters ; on the contiaenl urn furnishes that most generally prized. The ire-bricks come to Wales from the neighbourhood e town of Stourbridge in South Staffordshire j re 9 inches long, inches broad, and of suck 1688 that two of them extend 6 inches when placed ler with a thin stratum of mortal' between them.. valuable bricks are made in Wales from clay in beds in the coal formation ; and Flintahirft ihea a third sort to the Swansea market. jhiy from near Stourbridge, analysed by Bertbier,. ed him

fty refractory fire-stone lias been formed ng together one pai't of .clay with two or three of quartz sand and moulding the mixture. Suck I do not shrink perceptibly after having been I, and they have the advantage of being easily ned into any desirable form with the saw an4 . A mixture of 1 part of unburned clay, IJ to of burned clay, and 1 to parts of graphite, or lead, forms a mass that when once coated with glass that excludes the air from its surface, t indestructible.

i farnisbes a number of tocka which beii

104 The Mbtali.Ckgt Of Copper. '

composed chiefly of the same elements as the fire-claj possess in -various degrees its refractory qnalitiea These arc known aa fire-stones, and among them maj be reckoned sandstone, clay-slate, talcose slate, mici slate, and gneiss. The first mentioned is as a rule thi beat, especially when composed of quartz sand boonj together with a silicious cement. No general rule cm be given for recognising a good fire-stone ; the beal plan is to expose a fragment of the mass in question tc the action of a furnace and observe the effect produced Mortar for building the interior of furnaces should made of the same materials used to form the fire-bricl by bnnging it with water to the condiliou of a thii paste. The common lime mortar should by no mean) be employed where the work is to be exposed to a higl: heat, because under such circumstances it unites witl the silica, producing a somewhat fusible compound The hearths of reverheratory furnaces, and other part of the smelting apparatus are frequently constructec of a refractory mass which without being previonslj moulded, is worked on the spot and in the fumace itself, to the required form. In Swansea a quartz aanc used in its natural state, not only makes up an essential portion of some of the furnaces, but by gradually uniting with the mass melted upon it, play a an important part aa a flux. A mixture called brasgtu, used for forming temporary basins and hearths, into and overwhich fluid metal and slag are drawn, consists of clay and powdered charcoal or coke, in nearly equal proportions.

The Metalhtrgt Of Coppee.

. DESCKIPTION or 1 THE METALLURGIC PROCESSES ARB FERPOttMED.

Umost every copper-reducing region has furnaces

1 other apparatus more or less peculiar to itself.

iese Taricties arise from the system of reducing the

Ktal which may be customary, the nature of the ores

Ifael, or the judgment of the smelter. But all the

Dis may readily be referred back to four types,

[ are distinctly different in tlie arrangement of

. parts, and are also distinguished from

I other by the nature of the processes for which

b is particularly adapted,

I la the description of special processes which will he

ind in another part of this treatise, the apparatus

{tiired for each will be given in greater detail of

rial and measurement ; here will be found a

pital of the general cbaracteri sties of the four classes

which they all may be referred.

El. — Apparatus for roasting where the fuel ia muaed the ore. II. — Reverberatory furnaces. III. — la fwmacet. IV. — Refining hearths.

I'AHAaATUS rOB ROASTING WHERE THE FCEl IS MIXED WITH THE ORE,

J are exceedingly simple, sometimes consisting

Kb Bmooth pavement, or dry floor of clay, upon which

re is piled in pyramidal heaps, the larger pieces

placed under, the smaller above, the whole

tsted by temporary canals ot cVmrnie'*.) .f \jefsKA

a better circulation of sir, and sometimes covered b coating of powdered ore. The fuel forma tbe foun tion and serves to commence the combustion of Bulphurous constituents ivhicb are often sufficiei abundant to prolong chemical action and keep mass glowing for several weeks,

Anotber common form consists of a rectangt space surrounded on three sides by walls, and caps of boldiug a pile of 5 or more tons of ore. The fon side is left open to allow easier charging and ( charging, Small chimneys penetrating tbe mass, f tbe foundation of fuel, answer the same purposes they do in Ibe first-mentioned plan. An addition o separate fire-place is sometimes made to these 0] roasting floors, by supplying which with fuel 1 process of roasting is completed. A tliird arrangemi is occasionally employed for roasting furnace prodm It consists of a vault about 9 feet long, 6 liigh, i 4 liroad, one end of which is left open for the int duction of the charge of ore and fuel, but is aulj quently closed with a dry brick wall. A permani chimney carries off tbe gases and supplies a cert amount of draught to increase the rapidity of ' roasting.

Ii, Kevekberatouy Fuknaces.

This is the most important form of furnace used the copper smelter. Its plan of construction is Taric and depends on the nature of the ore to be treatedj fuel employed, and the process to be performed ; the name includes all furnaces with a separate f place, a hearth for containing the substance to treated, sitiuted below a low \aull, a.Q.i m tfiti*. -a

THE metalldhgt op corpEK. 107

ith a chimney. Fig, 14, page 127, represents one of English reverheratory furnaces used in Swansea; o presents the grate of iron bars upon which the fuel consumed; b, ih.e fire-bridge, which separates the e-place from the hearth or sole, s, Tlie gases paas through the flue, f, into the chimney. The originating in the combustion of the. fuel at e, Dow the leading of the arch a, cross the fire-biidge and carried forward by the draught generated in ! chimney, sweep over the hearth, a, hcatiug and jnging forward chemical changes in the substance ich is placed upon it. The flame, whose natural ideney is upward, rebounds or is reverberated from ! sm-face of the arch upon the metalhferous mass How, and hence the name of this class of furnaces, be charge is generally brought upon the hearth by lowing it to fall thj'ough a hole c, in the vault ; and r the sake of greater convenience, these holes have Squeiitly hoppers above them, ivhich being filled, can (emptied at once into the furnace. The furnace has Fo or more apertures at the side or end, which allow fi attendant to stir or otherwise treat the charge bile being subjected to the action of the fire, and tiicb also may be employed to draw off the substance ;er the process is completed. The hearth is occa- inally cleared by scraping the charge tbrougb a hole, I shown in the figure, leading ioto a chamber below, bich remains closed whUe the furnace is in action. The fire-bars are of iron and are often moveable, so ifit the workman may stir the fire more readily from Aair. The vault, the fii'e-bridge, the interior of the amney, and all parts intended to be exposed to severe; are constructed of fire-trick, "wViVe \Ni'i ciffiW:

108 The Metallubgy Op Copper.

walla are usually built of the cheaper common d bricks; all is firmly bound together with iron ti fastened with clamps and wedges. The sole or heart s, when the furnace is to be used for smelting formed of a mixture of sand and silicioua slag ; wh for an evaporating furnace, a shallow water-tight p occupies the same place. The metnCurgic proceH that may be performed in reverb eratory fumu embrace nearly all that are necessary for the reducti of copper from its ores. They may be employed I roasting and for oxidising, reducing and diasoln fusion. They are however expensive to build, i require proportionally a very large amount of fii since the flame playing rapidly over the surface of i metal, at s, rushes up the chimney while yet bal small per-centage of its heat has beeu given off.

Iii. Cupola Furnaces.

A cupola furnace consists of a shaft-like spa having a height greater than its breadth, enclosed mason-work, and in which the substance to be mel lurgically treated is melted, generally mixed, and intimate connection with the fuel. The height of i furnaces of this class used in copper smelting vw from 6 to 18, and sometimes reaches 25 feet; the requisite to carry on the process is forced in at ' lower part of the shaft by a blowing apparatus usm driven by water or steam. Fig. 16, page 154, may taken as an example of a cupola furnace; the space represents the shuft, cone or body of the furnace ; a the opening known as the tunnel-head or Mn ; which ore, fuel, and &\3iX axe 'wiUdiiifi

B shad xnd allowed thence to sink towards the sole, I At c, are openings called luylret, througli wliicli B air is forced, to supply the combustion which iefiy takes place in the prismatic space, a, which ia pown as the hearth; e, is the eye of the furnace, ouglt which the melted metal and slag formed in B hearth flow by a narrow channel into the basins,//. ie interior wall or shirt, h, of the furnace is cou- iBcted of fire-brick or refractory fire-stoue; the outer ul may be of common masonry. The front hearth, g, BE which the metal flows, is usually formed of coiil or and clay, in the condition of fine powder. The Reres, c, are generally made of cast iron ; but some- bea, as in parts of Sweden, they are formed of clay. I practice, a tube of slag formed by the cold air Miiag in at the tuyeres, and impinging against the mass, extends from the nozzel of the blowing the hearth, regulating the place where the air BS* Tliis nose is of much use to carry the air into m central parts of the furnace, and to protect the Kres from the destructive action of the hot gases; H its direction, length, and temperature are watched Dth attention by the careful smelter who regulates by appearance the proportion of fuel used ; hence arises B German metallurgists' adage, " You should seek a pod fumace-man behind his furnace." Prhe cupola furnace is the most economical of all htaratuses used for smelting. The fuel being con- pued directly in contact with the ore, subjectp it to most intense action, and the heated gases or imea passing on their way upward through the rioue layers of mineral, the latter absorbs a greater bt p£ the beat, so that they pass oS at t\ie tunnel.

! METAHnHGT OF

a low temperature when compared with thD t stream up the flue of a revcrberatory furuace.

It. Eefinixg Hearths.

le refiniug hearth (fig. 19, page 170) is used E contiuent for performiug some of the last proceai in the pui'ificatiou of copper. It consists of a d masSj b, having its upper part properly hollowed inb basin, a. The tuyerCj c, is furnished with a moves nozzel, d, through which a strong blast of air can driven at any desirable angle into the basin. A, vb the substance to be acted upon is melted. The t employed is usually charcoal ; the object of the ap ratus is generally to carry out a strongly osidiai fusion, and its size may vary so that from 100 to 5 pounds of copper may be treated at once.

I On The Generai, Principles Fkucesses.

Ov Hetallueoic

Tlie ore passing in the course of its concentrat from the hand of the miner into that of the ame has arrived at a conditiou of richness which will n rant a change from its lutherto almost excluaii mcclianical treatment, to one depending aln entirely npon chemical affinity ; the carrying out i iuporviitiou of which is the task of the metallurgist,

That chemical action shall take place, it is essen

that the ))arttclcs of one or more of the subataacee

dvooniposcd or combined be in an easily morel

eonditton, a dtate which is secured in two wajs

p$tJ/, hy jiroducing fluidity by beat. %c<mu

THE METALLtTROT OF COPPEK. Ill

solation in a menstruum wliicU rcmuina liijuid at crdinary teniperatiirea. The first method of treating ores is known aa the " Dj'y TFay," the second as the " H'ei IVay." Both methods are used in the metal- lorgy of copper; the firat chiefly where copper alone or copper and some of the baser metals are the valuable oonatituenta of the ore treated ; the second is often employed where silver aa well aa copper result from the operation, or where iron and copper vitriol are produced. The wet way in the reduction of copper is, liowever, subordinate to the dry way; and is seldom (or never employed alone for the production of fine al from the raw mineral ; it is, nevertheless, very lable because it enables the metallurgist to take itage of certain affinities, which cannot he made of by the other method, to effect a more complete paration of different metals, and also on account of smaller quantity of fuel required, which, in regions r in wood, coal, and roads, as in some parts of Spain Austria, is a matter of primary consideration.

Mxtallurgic Pkocesses By The Dry Way,

Uaaiting. — By this term is understood tlie heating of ore or metallurgic product to a degree less than Lt at which it mclta, and generally subjecting it at ! game time to the action of an atmosphere of gas, air, chlorine, or carbonic oxide, for the purpose of inging about chemical cbangea. It ia evident that s circumstances favourable to this process are fineness the particles and porosity of the substance subjected the action of the gases, frequent stirring, by which &esA Burface ia exposed, and a rapii q1

ram ubtallubst op ooxvtsk-

gaseous atmospliere, all of which tend towards bi the particles of the different substances in closer with each other.

Four kinds of roasting are distinguished, a are all more or lees employed in the treatment copper ores. First; owidising roasting is that by wliiA the quantity of oxygen in substances subjected to it, it increased. Second; reducing roasting, where the pro- portion of oxygen is reduced by the operation. Third] chlorising roasting has for its object the forraatifln of the chlorides of the various metals. And fourth f volatilising roasting, where it is sought to drive out certain volatiUsable substauces from their comhinatiou with the ore, as water or sulphuric acid break, Genfr-' rally, in practice, two ot more of these processes go oBj at the same time.

Fusioii. — Taken in a metallurgic sense, this term designates that process by which a mineral is brought in connection with certain fluxes or re-agents, by meAni of a greater or less heat to a fluid condition. When in this condition chemical changes generally take place, and the mass, under the influence of gravity separates into various parts, the hea\iest constituent being below and the lightest above. Several species of fusion are distinguished by the nature of the changes that are produced.

First. — "When substances having different degrees at attraction for oxygen are melted in contact with an oxidising body, as atmospheric air, those ha\-ing the greatest affinity for that element are combined, and generally separate fi'om those less easily attacked in the form of gases or slag. This is called oxidising faeum, aa exceilent example of whicli ms. Vt iVud.\&d,\iv

THE METALLUHGy OP COPPEB. 113

it process iu tlie operation known as refining in tli6 dsti method of smelting copper ores. Here, over J surface of a melterl compound where copper may accompanied by lead, iron, cobalt, antimony, lenic, and sulphur, a stream of air ia nlloned to pass ; Moria formed of the oxides and sub-osides of all of ! metals that may be present, colleets and is jed off, while by far the greater part of the copper mains in a nearly pure state. When the object of fusion is to snbject either Itural or artificial compounds of metal and oxygen ; the action of some substance having a very great Enity for oxygen, as carbon or hydrogen, for the ITpose of allowing the oxygen to be taken away and nducing an un combined metal, the operation ia nown as a reducing fusion. An example of this will i found by referring to the poling process in refining iper. Here the melted metal is saturated with the fl)oside of copper; the green wood which is intro- decoiHposea into carbonic oxide, carbnretted fdrogens, and other substances capable of forming ftseous compounds with the oxygen of the suboxide, hich, passing off, leave the metal in a comparatively

B condition,

"When two bodies, being brought to a fluid condition, t upon each other so that a part or the whole of one

iduces with a part or the whole of the other a new mponnd, either valuable in itself or, as is more gene- Uy the case, which on account of its different melting (int or speciSc gravity can be separated from the bfitances with which it ia mingled, such proceaa is Qed dissolving fusion. An instance of this kind of

ioD is furnished by the old loeea tiiuOitvy

METiLLUHGT OF COFFfiB.

once much eniployei] for the separation of silver copper ; copper, holding silver, ia melted with lead, lead dissolves the silver, and by a subsequent operal Lereafter to he described, the argentiferous lead drained from the compound.

Precipitating fusion, takes place when an element a melted compound is separated or thrown down the addition of a second body; the term is genei used to designate the decomposition of sulphides means of iron,

In practice, two or more of the above-di varieties of fusion may go ou together, and frequent the occurrence of ouc, necessitates the occurrence the other; thus, in the example just mentioned the reduction of the suboxide of copper in the procetf of poling the gases are at the same time oxidised. such case the name is drawn from the nature of change which the element undergoes that is the object of the metallurgic process. The distinctions mainly valuable in assisting the student to unravel complicated series of re-actions that go oa within walls of a smelting furnace.

lAqualion is employed for separating the constituent! of a mixture made up of substances with differen melting temperatures, by applying a gradual heat tO' the mass, and allowing the easiest fusible constituent to drain or filter from the more refractory. It cannot be used for dividing chemically combined suhstanceij and at beat produces only a partial separation. For these reasons it is gradually being superseded by recent and more perfect plans. Its most usual application it- to the separation of silver from copper ; three part) copper holding a small per centage of silver are tneltod

1 eleven parts of lead, and the compound aUowed to I gradually ; a greater part of the lead forms an y irith the fiilver, which remains mechanically igled with the copper, and when suhsequeutly the IS is cast into disks which are placed on their edges O a peculiarly shaped hearth and subjected to a t slightly above that necessary to fuse lead, the alloy

lead and silver filters out, leaving behind a porous of impure copper. Both of these compounds then be treated to obtain their three constituents

B purified condition.

Metallukgic Processes By The Wet Way.

By a metallurgic process by tlie wet way is under- )d the bringing about of required changes by aolu- t in some menstruum that remains fluid at ordinary iperatures, which is generally water, or water con- ling an ucid or a salt. The employment of this thod has been much extended in modern times, and the metallurgy of copper it has in several instances en tlie place of the dry way, eapecijilly in the isola- l of silver when it occurs iu small quantities in ipany with the less valuable metal. Ziervogel'a itod of separating silver from copper consists in jecting the ore to an oxidising rousting, dissolving the sulphate of silver thus formed, with water, and I precipitating the silver in a metalUc form with jer. By the process of Augustin a chlorising iting is pej-formed, and the chloride of silver thus luced is extracted from the mass with which it is id by dissolving it in a solution of common salt. metallic silver is then obtained as fthove, by re- J

116 The Metallurgy Of Copper.

cipitation with copper. Cement Copper is obtaine* precipitating the metal firom a natural or artificial i tion of its salts by means of iron. These proc will be found treated more at length in a subseq chapter.

The Metallcegy Op Copper.

ms Obbh or Coffeb; Detiils or Tax Yabiw D UT TBB Bbsuction ot Cofpbr Oru ; Sefabj,-

n OF COFPBB FBOU OTBEB MsIALS ; NaTUBG OP AMD MANNER

Makihq the Alloys op CoppEa; The Woekinq of CofPEB D MiMnfACTDRE OF CupBEOiis Phoddotb; STiTiallOS.

Chapter Ix.

Jbi describing the numerous and various processes have been contrived for reducing copper from its

!j the plan that recommends itself for its simplicity completeness, is to select from the chief copper-

incing lands of the world several characteristic

:hods, and consider the processes peculiar to each in 1, and successively fi'om the earhest heating of the

leral to the casting of the saleable product. Thus chemical re-action peculiar to each variety of ore be included, and no essential apparatus or opera- be left unmentioned. The following have been en as best adapted for securing the objects in view :

The Smelting Of Copper Ores In Walesj The

English Method. The Smelting Of Copper Oses In Mansfeld

PRUSSIA; THE CONTINENTAL METHOD. THE SMELTING OP NATIVE COPPEB, AT DETBI

In The United States.

The first is in use for reducing the vast qiiiintitiea it ores varying in composition and richness, which are ilm ported into South Wales. No other system equals it ii securing a regularity of production where the changa of the per-centage of metal, and the chemical compod tion of the mineral are ao sudden and unexpected. i

The second gives a represent !it ion of the processes i use in the furnaces on the continent, where as a rule ore, being the product of a limited region, suffers n little change in its nature from year to year; andgSii the admirable method of Ziervogel for aepjiraliag sili and copper was invented and is brought to its grestw perfection at Mansfeld, a description of the variooi operations of which it is composed will be found their proper place in this chapter.

The third example illustrates the method employe! for separating the native copper from its mixture veinstone, as practised with the minerals of Li Superior.

GENERAL PaiNCIPLES OF COPPER SMELTING.

One or all of the following peculiarities of coppecSl at the foundation of most of the methods which are i use for purifying it by the aid of fire : — 1st, its attracti( for sulphur is greater than that of any of the metals wil which it is fouud in combination, as iron, lead, mcketf cobalt, zinc, arsenic, antimony. 2nd, its affinity for oxygen is very araall, less than that of any other metsl likely to occur with it, except gold and silver. The metal- lurgist, by allowing it to combine or remain in coml nation with the sulphur usually present in its ores, has conJflrativel J fusible compound, which ou account ofil

idity or peculiar specific gravity, can readily be iKFated from many of its less fusible, and lighter or ivier, impurities. By roasting his furnace products, gets rid of sulphur which would be troublesome in Mequent operationa, and by subjecting the fused ;tal while in an impure state to the action of oxidising mta, as the atmosphere, he brings about combi nft- Ds in the adulterating substances without the ci ing materially attucked.

Bcetallchgic C

Tion Of The Ores Coffer.

For the purposes of tlie smelter all the compounds om which copper is obtaiued may be arranged under tree heads.

. Native or uncombined copper. Tiiis is principally nnd on the Ural, on the borders of Lake Superior ad in South America. The latter country sends much irf this copper to Europe to be piirified. It occurs enerally in small grains, and is mingled with red dde, malachite, pyrites, and earthy gangue ; it usually Dfltains only traces of arsenic and is otherwise very

re, producing 60, 70, and even 90 per cent, of metal.

sLake Superior mines produce three sorts: 1. Mass

tr, which consists of vast blocks, weighing as high as

100 or 9000 lbs., and containing only a small quantity

silver, and a few nodules of earthy veinstone as im- uitiea. 2. Stamp work, or small pieces of copper which dve been cleaned of their gangue by the stamps ; and

Barrel work, which is the result of washing the wder coming from the stamps, and contains from i to 60 per cent, of metal.

II. Oxidised ore. Except ia Australia this kind of ore is found in comparatively small quantities, and at i Kuiited number of localities. Tliis division include* Mlack oxide of copper, which is a product of the de- ooinposition of other ores, and usually is accompanied by manganese and iron. Atacamite which contains frpiB 45 to 50 per cent, of a very pure copper ; the carbonalti coppfr which occur in Australia, Africa, and the Ural, iid various other localities. They are generally purt. lutd give good copper; but when formed by the decom* |>ositioii of other minerals, they have always a suull quantity of adulteration, Silicales are found in the Vnil, and in South America ; they are easily reduced) and furnish a pure copper.

III. Ores containing Sulphur, Arsenic, and Antimotif. From these compounds by far the largest part of the- copper brought into commerce is wou. They are the most difficult to reduce, arid require numerous aiA. complicated processes to carry off their many impurities. In the ores containing arsenic and antimony, silver is frequent and valuable constituent. Copfier Pyrites: this is the most common ore of the metal ; it is found Ipcnorally in company with quartz, ealcspar, heavy spar, CArbonate of iron, and the sulphides of iron, zinc, and 1tr*ouic. When entirely pure it contains 34 per cent, of , but on account of the adulterations, which it ia )tu|HMiiblo to separate entirely by the most careM MUutg,it generally comes to the furnace holding from Ut Ifi per cent. At Fahlun in Sweden, where this Uwtfkfdithc average richness is ft-om !2 to 3 per cent.; H\WM in Sweden, 5 per cent. Variegated copper WV ssMkUllu when pure about 65 per cent, copper, smt IM fWy widely distributed. Sulphate of copptt

! Metallckgt Of Cofper.

a in small quantities from South AmcrtcH, where it IB evidently formed from the decomposition of other The waters of various mines contain this salt in Tion ; it is then won by the process of cementation, 1 produces a copper which depends for its excellence the absence from the solution of arsenic and mony. Gray copper ores contain arsenic and timony, and occasionally so much silver that that ital is the most valuable of their products. These s are found in but a few localities, and on account of I disposition to crush easily to a iine powder, cannot concentrated by washing without much loss. Their jper management, to obtain the copper and silver [tarate and sufficiently pure, ia one of the most ficult problems set before the metallurgist. The ipbates and arseniates of copper arc widely dis- ninated ores, but are not much worked; a small mtity of the latter reaches Swansea from Chili, and odnces from 30 to 35 per cent, of metal.

Chapter X.

S>ii.TIiia or CnFPES Ores in Wale ; the Ek9LI3H Msthoi

The plan of reducing copper from its ores which J wn distinctively as the "English Method," i icl is to be found in use, more or less modified, ut arly all the countries where Anglo-Saxon energy has mted smelting works, — in the United States, in the rath Sea islands, even in central Germany, — seems to ire originated in essentially its present form near it is now to be found employed in smelting

nearly half the copper produced upon the globe, — oi the southern shore of Wales. j

The distinguishing and most obvious peculiarity ( this method lies in the use of reverberatory fumaoes-J the exclusion of all others, in carryiug out its Taiial processes, and in the fact that the sulphur of tho cg;B. made a chief reducing agent, instead of the coal m carbonic oxide which play the same part in the cd furnaces, tlie action of which ia yet to be describes It further differs from the usual continental method] the last operation, the blister copper being here purifii and made malleable in the Game fusion, and tl product to market in the form of barsoriiigo ready to be wrought directly ; while the coutinenl furnaces generally produce, as their merchaittab product, what is known as rosetle copper, — thin disl of metal holding so much suboxide that they bra readily with a abort red fracture, and must be su jectcd to a subsequent refining before they can ' hammered or rolled.

COMPOSITION, OBIGIN, AND MIXING OF Oa£S.

The English method is adapted to the reductioo all classes of ores. It is ysed in smelting the pradu( of the mines of every quarter of the globe,the ri sulphides of Cuba, Chili, and New Zealand, the pooi flulpbides of Cornwall, and the valuable osides ai silicatea of Australia.

The following table will give an idea of the compa tioa of some of the moat abundant of the ores that a hronght to the Swansea smelting works : —

TttE StEtilXmiffZ OP COPPEB.

ChUi.

Zealand. AvdraUa.

tat besides these ingredients there is generally it a variable quantity of tin, antimony, araenicj , nickel, cohalt, manganese, or silver, with alumina, nesia, or lime.

he classifying and mixing of these oi-es rendy for [ting is a subject of the utmost importance, affecting cost, quality, and quantity of the metal produced the subsequent operations. It ia evidently a

TOE METALrUHGT OF COPPEH,

chemical problem, and its proper solution can onJ on analyses and ft knowledge of the action o various bodies present, when brought by fire to a state. It has been shown that the following cond are to be sought for in making up a working mi of ores*: —

Isl. The copper must not be under 9, nor oi per cent. ; if under the former it is unpiofitably if over the latter, the alaga have a tendency to ct copper, creating a loss.

tid. The mixture, after undergoing an ort calcination, should fuse easily without the necesi adding flux, giving a clean and easily fused slag.

3rd. The matt, or coarse metal obtained frot first fusion shall contain, as nearly aa possible, J cent, of copper.

4tb. The impurities which will make the qua! the copper lower than that deterraiued upon shou rejected.

In forming this working mixture the rich oxide carbonates are not used, but are retained to be br ill after the reduction is partly completed.

The average composition of all the ores smelt one of the Swansea works during a considerable j was as follows: —

Aluaiina

Id

Magneuia Copper Iron

Othw me

3. Wspjer, F.aS.,

rwi.Mae

anaio-ini

qCSc

THE METALLCHGr OF COPPKR.

Solphnr

CarboDio acid — oxygen otiiJ

it in considering the reactions which take place a allow the various processes, Tve may regard chiefly of these substances, and consider the ore made

rMTTiiinv

IKTNABY OUTLINE 07 THfi OBDEU AND K

I Fbocesses Constitutinq The English Method.

studying the English method of copper smelting, Jistinct processes may be distinguished. These Beparated from one another by the charge or lal being transferred at the end of each from furnace to another, and by the difference in the the products resulting from each- They are Hows : —

Calcination of the mixed ores; a portion sulphur and other volatile ingredients are driven uid some of the iron irhich becomes dispossessed of olphur is oxidised.

. Fusion or boasted ores for coarse metal.

roasted ores and the carbonates and slags which mixed with them, being melted, yield two products. Slag to the amount of 65 per cent, of the whole rge, about 8S per cent, of which ia thrown away as too poor in metal to pay for TeTOeVt.TO, -aud.

01

remainder returned to ihe fiiroace. Slid. MaU coarse metal, to the amount of about 86 per cent, w contains about 30 per cent, of copper, and aiter gn latioD goea to process III.

III. Calcination of granulated coarse va Tlie process resembles No. I. Mucb sulphur and a of the other impurities are driven off as gas, and iron and copper present become partly oxidised.

rV. Fusing the calcined coarse metal. result of operation III., together with slags from op tion v., mixed with foreign carbonates or oxidea, b melted, produce two products. 1st. Sharp slags, stituting about 25 per cent, of the fall from the fiin and holding 1 to 2 per cent, of copper. 2nd. A J called blue or fine metal, containing about 60 pet< of copper, and being about 75 per cent, of the fall i the furnace ; tliis goea to process V.

V. Roasting the blue or fine metal. The ] produced by process IV. is freed, during this opersi of much of its iron, silica, and sulphur ; here, also, products are two. 1st. Slag or scoria, amounting b per cent, of the fall from the furnace, holding abou per cent, of copper, and known as roaster slags ; 2nd. Blister copper, or pimpled metal, of which abon per cent, is copper.

Refining the blister copper and polino. iron, nickel, cobalt, zinc, sulphur, fee, are oxidised removed, and the suboxide of copper which dissolve the metal reduced. — Result, malleable, tena dota,'

THE jrEJArXUIlGY OF cori'E

Process I. Calcinatiox 01' The Mixud Ores,

The object sought to be accomplished by this prt to drive off the water nnd the volatile arsenic, anti- iny, and all of the sulplitir that is not required to Di a sulphide or matt, which shall amount to per cent, of the product of the nest following fusioa ; 1 further, to form from the sulphide of iron, oxides it will combine readily with the silica of the ore to m B slag. The operation is performed in what is own as the calcining furnace or calc'mer, which is

klarge rCTcrbcratory furnace, haiing the form shown

I the accompanying 'drawing, in which one corner is

resented as cut away that the interior arrangement

iay be better seen. The size of this apparatus varies:

! hearth, s, is usually ]6 feet long, Rud 13

d; it is formed of refractory bricks set on edgc

1 firm Ir imbcfJ fled in fire-clay. The fire-brick a;

A, desceocls rapidly towards the bearth as it approftcbu tlie flue, F, and it ia perforated with two holes, c, which are capable of being closed tightly. Each ai of the furnace is supplied with two doors, of which a is slkowii at D, and through these the workman stj the charge, and watches the progress of the work. ] the hearth, and represeuted by v, are apertures leadii into the vaults or cubs, v, that lie beneath the funuM and serve to receive the ore, which, when ready, a scraped into them. Above the furnace are placed iron hoppers, t t, into wliich the ore is thrown being dropped upon the heai-th. The flue, F, the vapours off to a stack or cbimuey, which n belong to this particular fuvuace alone, or may common to all the furnaces of the establishment : adoption of the former or the latter of these depends largely on the fancy of the manager or In one iustance the necessity of a tall chimney obviated by carrying the fumes and smoke from large establishment (Cwm Avon Copper "Works) througll a long culvert to the top of a neighbouring mountun, where, at the distance of a mile and a quarter from works, the heated gases rush into the open air. The draught produced by this expedient is said to be almost sufficient to carry up a man. At the corner of the fire-bridge, b, is an opening, o, which is arranged with a damper, so that it may be opened or closed at the will of the workman, aud air is thus allowed to flow over tbe heated ore in the hearth, s. The deep-set grate-bars, f, rest loosely in their places, and support the coal which consumes in the fire-place, i. All parts of the furnace that are exposed to great heat are formed of Sre- ; the exterior walls ate of the ttsual red

Of Coppeb.

13U

ik, and tlie whole etructurc is bound or cramped ti wrought iron rods, that are passed tlirough the in various directions, and are keyed on the r to cast-iron bearinff-plalcs. nstead of this single furnace, some establishinenta provided with calciners having two, and even three, , one above the othePj which are used under the

ression that an economy of fuel is thus obtained ; s have the ore calciner on the top of the smelting aace ; while a third plan ia to connect the calcining irth with the smelting hearth upon the same level, 1 heat them both with the same fire, [he fuel used in the furnaces of Swansea is, as has dy been shown, the mineral coals of the Welsh The deep fire-place ia especially contrived to I their proper burning, and to enable the work- fa to make use of the support of clinker, which forms

1 the semi-fused ash. The workmen are able to date the draught and manage the fire from beneath, I the nnconsumed results of combustion fall into the

iDodtous ash-pit, k.

le mixture of ores having beeu satisfactorily made,

urried to the large hoppers, T T, and at the proper

! let down upon the hearth, where it is spread laily over the fire-brick surface, covering it to the ith of 6 or 8 inches. The quantity of ore put in iea, according to the size of the furnace, from three rii tons. The fire is in the beginning kept low, and I first hour or two serves to heat the charge gradually tout bringiug about important chemical changes. It occasionally moved with a long rake, known as a n'ny rubble, that is introduced iirom the side doors, aarres to expose a new surface to the action of the

fire and air. The heat is gradually increased, ao tha at the end of about three hours, the charge ia vmHj red, aud afterwards yellow-red ; but Eince this heat penetrates only to about one inch below tlie surface, the oro muat be often turned over by of long iron paddles, that no part may escape the actioa of the hot gases. The aperture, o, at the corner of the fire-bridge, is left open to an extent deemed necesui for supplying the required quantity of air to secure proper oxidation, and the draught rushing in at A hottest part of the hearth is rapidly spread otot & whole surface.

It is evident &om the object sooight to be boCQB plished by this roasting, that the length of time saiy to calcine the ore does not depend upon amount of copper, but upon the amount of sulphur it contains. The usual time is somewhat over nine hoiaa and when the ores are especially rich in sulphur and silica, even as much as twelve hours are needed.

In those furnaces where the ore is calcined on hearths, the charge to the amount of about four tona k firat put on the top of the furnace, where, after becoming dry, it is passed to the upper hearth by apertures in the arch. This hearth is heated from below, and serves to bring the ore to a condition that fita it for rapidly calcining after being passed to the lower hearth. After remaining here for about hours, and being subjected to a strong fire, it is ready for taking out.

In either furnace, when the ore ia sufficiently calcined, it is scraped through openings into the vaults or mit below, where it is completely drenched with water, in which operation much aulpUwetted tydroeu. is fjivea

I'HE jfETALLtlBOY OF COPPElt.

ff, and a corresponding quantity of oxides fori lie <we is then removed from the to n jnrS, ihae it is allowed to remain stored for some time, pace it is found tLat the decompositions which take 3kx in the damp powder aid in securing in the next melting a matt richer than that obtained when the es are fased directly from the calciner. The chemical changes which take place in ft calcining Eoinace are extremely simple when pure ores are Iresent. As the heat rises, some of the sulphur of ia iron pyrites volatilises, and then sulphurous acid md the oxides and snlphates of some of the metals formed, "When at the end of the process the tem- perature is raised very high, moat of these sulphates mposed, and the oxides remain behind. "Whea Uttmony and arsenic arc present in the ores the actitHi fe Boraewhat more complicated. During the earlier part of the operation, when the sulphur goes off, the two metals accompany it to a small extent as sulphidea. When the heat is raised a little higher, and but a small mount of air is admitted, the oxide of antimony and irsemotis acid are formed, both of which being volatile re carried off through the chimney. But when the eat is still further increased and more air admitted, tiese two substances take on more oxygen, and com- ine with the bases present, forming refractory antimo- ifites and arseniates, which remain with the mineral, cases wlierc the establishment lias sufficient ore the purpose, those holding arsenic and autimonjr calcined alone, and slowly, until nearly all of B disadvantageous 'substances are driven off, and 1 mixed with the purer pyritiferous ores whieK ilf the snJphur necessary for making a :

B lar crtibhhmeot, soflied from a ffot, c€ looHtif, B often eaabled to make exceUent oies of bst Bwdecmte poritr. The tin thib be ovigiiul mineral cannot be remored hj Aboot 1 ewt. of coal will be rfqaired ta laae a ton of ore, and at tfae end the process &om 12 to 15 per cent, of sulplior vill still remaio in the .diare. In calcinio three men are employed to alteud each fumaee br day, and three by night ; ) re paid by the watch, and but little skill is required to carry Oat the process.

pnocEss ti-

-FfStON' OF THE ROASTED ORES FOK COARSE METAL.

The object of this operation is to concentrate copper in a sulphide or matt, aud remore from roasted ores the silica and earthy matters nith t1 they are encumbered. Tiie furnace iu which tfae pro- cess is performed is represented in the adjoining dmwiug. A lai furnace of this class has a hearth, c, 14 feet long by 11 feet broad, and measures on the exterior of its walls 22|- feet by 15. All the parts exposed to the fire are built of the best fire-brick, of vLieh 8500 will be required in its construction. The grate, e, aud the fireplace, r, are arranged for burning coal iu a cUnker-bed, and their dimeosions are made to bear a proper proportion to the area of the hearth, c. The workmen can descend into the ashpit, a, to regulate the fire, and at tlie opposite end of the apparatus the door, D, is used for drawing the melted slags from the hearth. A hopper, u, on the top of the furnace serves to collect the ore previous to letting it down uon the

I a hole in tlie loivermost part of thia ftrraiBhea n means of tapping off tlie meltet at collects during the smelting. :oDstruction of the bottoms, b b, requires much 1 the part of the furnace-mau ; the material of they are made lias already beeii spoken of in

r Vm. It is a highly silicious sand, and ohtained from the sea shore, where it 1 one a process of winuowing by the winds, iich of the lime tliat originally existed in it ia m of small shells has been carried away. Twoi of slags are first melted on the floor of the made vault ; sand is thrown upon this to the of about 18 inches, calcined for a couple ot' ind theu shaped and beaten down ; some slag irowu iu and melted on the surface ; a second tf sand 4 inches deep follows, and above thi: lyer of slag ; the whole being subjected to lmtinga is ready for use. These bottoi

will sometimes last IS months, but are gen< so durable ; they absorb a considerable qm copper, irhich is thus locked up as dead capital, mi their gradaal melting out, they supply the ore with u important silicious flux.

The roaatet! ore from the yard is weighed out i hundredweights, and carried by the workmen to tb hopper, H. At this stage of the process, the rsi carbonates are introduced, since the absence of sulplna from their composition makes it unnecessary to subjeOl them to a previous calcining ; besides these the alagv rich in copper from process IV., arc here worked ot The amount of the charge will vary with the size ef the fnmace, and the fusible properties of the ores, but it generally weighs from 3 to tons, and is made as follows : —

Caldned ore bom procees I. ... 33 cirt. Kawore 20 „

Bliarp Blag frnin process TV. ... a „

To this, when a fluid slag is sought, silica and fliWr spar ai:e added. The charge is precipitated into toe furnace by drawing a slide from the bottom of the hopper, and is spread evenly over the hearth. The doors are closed, the air holes stopped with clay, and the heat raised as rapidly as possible. Through small apertures in the door and cbimuey, the workman watches the condition of the interior, and regulates his draught and fire accordingly. At the end of five hours when the furnace has reached a white heat, and all appearances are favourable, tlie door is removed and a loDg rnke passed througU the ftwiA cta-oanta, see if

; shale charge is perfectly fused. This being tke

Hae, the workman after allowing the mass to settle,

B the operation of ihmm'mg, that is, drawing off

G or slag, which has formed, and from its low

c gravity floats on the surface of tlie matt ; thia is

s of a long scraper, the slag being removed

f the aperture, d. experience is required

Srly conducting this operation, and great care is

teasary in drawing the scraper along the surface of

i metal, so aa not to take oat any of the valuable

r stratum along with the slag. When the work-

B by a want of attention allows copper to mix with

le slags, so that they hold more than about a quarter

& per cent., he is compelled to resmelt them free of

: a regulation that serves as a check to secure

1 working. When the furnace is skimmed, it is

e usual plan to let down a second charge of ore, and

! and skim in the same manner as above, before

Ispping the hearth to let out the matt. When auffi-

I'dent metal is collected, the tapping is accomphahed by

breaking out the clay stopper, and thus opening a com-

Imunication between the lower part of the hearth and

! exterior. From this aperture the matt is run

nirectly into a vat of water 6 or 8 feet deep and 4 to 5

square, at the bottom of which is a box with a pei'-

rated bottom that receives the granules thus produced,

1 which may be raised by a craue and the contents

noTed to the yard to dry ready for the next operation.

Bother plan is to run the matt into moulds, and thna

stamped to a powder before g

3 pigs,

D proec!

B going

. Since at the time of throwing the ore into thfe J tlie henrth is at a high heat, smelting soon

in ; the 8ul[>iiidc3 of iron and copper are formed aud" sink to tbe bottom. The silica combined with copper,< gives it up to the sulphur, combines with the oxides of iron and other bases, and rises to the top, forming & distinct layer of slag. The tin that may be present goes partly into the slag as an oxide, while the antimony and arsenic combining with the copper ai absorbed into the matt. Where insufficient sulphur is present, the copper willuot all go into the matt, huts portioa will reduce to blister copper and fiill to t bottom, and at tlie same time the slag will be found fj hold suboxide of copper.

The matt or coarse metal produced amounts generally to about 3i per cent, of the charge, and holds about 30 per cent, of copper, 34 per cent of iron, aud 30 per. cent of sulphur. The slag contains about 70 per cent* of silica, the remainder consisting of various bases; it is broken to pieces and cai'fully sorted, all pieces con* tainii]g globules of matt being returned to the fumacct again, and the remainder, which is generally not allowed to contain more than quarter of one per cent., is caal away. To produce a clean slag is a primary object with the smelter; and tlie size of the furnace, the amount of the charge, and the length of time employed for fusion, are all considered as influencing the quantity nf metal that remains among the silica.

PROCESS 111. — CALCINATION OP THE GRANULATED OB POWDERED COARSE METAL.

The object of this process is the expelling of a large portion of the sulphur that forms part of the powdered coarse xnefal, the formation of oxides oi c'p'ftt wad iron

m the sulphides, and tlie driviog o£f of as mucK rs isible or the antimony and arsenic. It is performed & furnace similar in its general features to that used C the calcination of the ores 'm the first process. The powdered or granulated matt is transported to

ipera on the top of the furnace, and let down upon

hearth in quantities varying from to 4 tons.

da mass being easily fused, great care is required not

raise the heat of the furnace too high at first, in lieh case the powder would clot, and, by adheriug to shrieks, prove prejudicial to the furnace and to the mpleteneas of the calcination. When a charge is let to a furnace it is first brought slowly to a visible red, A then the fire is cautiously increased until a bright i coloiu" is reached, which should require at least li mrs. This temperature is continued till tbe charge a been in the furnace 2i hours, the attendants stirring ' turning it over with iron paddles every one or two mrs.

Ihe holes leading into the cubs are then opened, and e charge scraped through ; water is thrown over the wider whUe it is yet in a heated condition, and when it is carried to a heap to await its transport to IDccsbIV.

The chemical changes that take place here are very Btilar to those described for the first process of cal- ling. When arsenic and antimony are present it is ell to lengthen the action of the fire that they may

carried off, but care must always be taken that JU

per cent, of aidphur remain in tbe charge th at suext following process may proceed properly,

XaOCEBG IV. — FfSlON OF THE CALCINED COJ

The object of this fusion is to carry off a large parti of the iron with which the metal is stiE mixed, and t produce n matt which shall be a still richer sulphide of I copper. It is carried out in a furnace which differs sO I slightly from that employed in process II. , that it does I not require a particular description. At this period I again, as at the bcnning of process II., the rich I foreign carbonates, and tliose sulphides and orides con- 1 taining little irou, can be introduced with profit. The I charge of a uanal furnace consists of about 52 cwt. and J is made up nearly as follows : —

Kefiner and roaeter Blag (prot'csBes V., VI.) 4 „

Beside these substances, copper scales from. mills and the cobbing or broken hearths are frequently added; and among so many elements it becomes A difficult matter for the fumacc-mau to know in what proportions he shall make hia mixture. The only criterion is deduced from the action of the first charge; hence it sometimes happens that instead of getting OB a product, a nearly pure subsulphide of copper, he obtains a matter very largely adulterated with sulphide of iron, and much copper goes over into the slags : failures which must be remedied by a rc-arragcment of the proportions of the elements of the chai'ge.

The lantcnh in the ptoportiona abma mdicated, or

TOE METAXxrcGy or corK

Bucfa quantities as tlie judgment of the furnace-maii KggestB, are brouglit on the lieartli through the liopper

working door, and spread evenly over its surface, ffhen this is done, the doore are closed and luted, and lie fire regulated to give out the required heat. At Hie end of an hour incipient symptoms of fusion appear

well in the softening of the mass as iu the evolution gaseous matter j and in about three hours after

jvging, two layers appear on the hearth, the upper

ick and undissolved, the lower a thin fluid. The

St is increased and all the solid matter melted ; the fased mass occasionally stii-red, and the pieces adhering io the sides of the furnace are struck down into the hearth, and at the end of six hours the separation of the charge into two layers appears to be complete. The slags arc then skimmed off as in the previous process, and the matt which remains on the hearth, is either tapped off into vats of water and granuhited, Tiien it is known as fine metal; or the charge is run

ito sand-beds and moulded into pigs, when it is known

I blue metal.

In this process the silica of the slags and furnace hearths, absorbs the oxide of iron which has been produced by the roasting ; the copper which may be taken up as an oxide by the slag, is removed again by iming iu contact with the sulphide of iron that gives a its sulphur to the former metiil, which then collects ! the matt, or coming in connection with the oxide sihcate of copper, gives metallic copper and ilpliurous acid.

The mati or blue metal obtained, is, when the ro- itaona have been complete, an almost pure Bub< ide of copper; but sulphide of iron is always

THE MET.4LLDWttf

present, and the average composition at—

Copper 73-0

The slag, wliicli is a pro to- silicate of iron with various impurities, contains from 1 to 2 per cent, of copper; and on account of its brenkiug into sharp edged

J&agments, ia known as skc— -' — '"

operation II.

It goes back to

Process V. — Boasting The Blde Or Fine Metal.

It is Bought by the fifth operation to expel all tha sulphur, and to obtain a copper as free as possible from metallic impurities. The means adopted are to expose the matt to the action of heat and the oxygen of the air; and by the addition of a small amount of silica to take up the iron and other oxides as slags.

The furnace is similar to that described for pro- cess II. ; but is not furnished with a hopper, since iht charge, instead of being put in from above, is introduced at a side door. This is done by means of a long paddle, upon which each pig ia transported cai-efully to it* proper place on the be art h. The charge amounts usually -to 3 to tons of metal, or enough to produce 2J to 3 tons of copper. The furnace is much cooled by the introduction of the charge ; but as soon as all is in, the door is closed and luted fast, aud a strong fire g;iven, so that fusion soon commences. The highly heated gnses striking the aurfB.ce of tl\e l%a caitae§

H them to trickle dovrn in drops, in this waj exposing H much surface to be oxidised, nnd mucli sulphur to H escape as sulphuroua acid. The heat is raised until the H (OEteiits of the furnace are iu a complete state of H fusion, in which condition they nre kept some time, 'H iflile sulphurous acid escapes in considerable quantities, m canning a boiling in the mass. The five is now allowed B to abate, aud the door of the furnace is opened. The H result of the entrance of cold air is to cause the forma- j tion of a crust on the surface of the fluid, and its BBdtiou from a bright, to an incipient state of redness, portion beneath, however, still continues to Eulphurous acid gas, which as it rises iu bubbles, PPRs a motion among the pailtcles that answers the rjmrpose of stirring. The door is closed when the I temperature falls too lor, and the mass is again B brought to a high heat. This smelting and cooling ia

continued until the gaseous matter ceases to be given

o7, and the process of oxidation is known to be W Jnfficiently advanced. The door is now tightly closed, I and the fire renewed, and increased gradually for six '. lionrs, during which time sulphurous acid still continues § to escape. Up to this stage, slags, on account of the Blow temperature, have not begun to form to any P Emount ; but now the fire is raised to its highest point, r and the silica which comes from the walls and bed of

the furnace, and from the sand that hangs to the pigs, unites with the oxides of iron and copper, and other F'bases present, aud rises to the surface, from which it lis caxefuUy skimmed. An impure metallic copper uradually fills the hearth of the furnace; and at the nnd of the process, which lasts about 24 hours, this is, tapped into rectangular moulds formed in the floor

the foundry. This product is kiioini as coarse cojipeT, ied copper, pimpled copper, or blistered copper, according to quality; but tlie term, coare copper, is sometinei applied to all these kinds except the blistered, If the cooling or settiyig of the ingot is accompanied by contraction, it is termed bed copper, and other metali as tin, are then known to be present; when the sur&w is covered with pimples, which indicate the presence of anlpbur, the product is called pimple copper : and whrai the copper is good and ready for refining, it becoma covered with Sakes or scales of the oside, and is then known as blistered. The coarse copper contains from flO to 95 per cent, of metal, and the blistered copper 95 to 98 per cent. ; the remainder being in both cant cliiefiy, iron, sulphur, silica, tin, antimony.

When the pure variety of the metal known as copper is required, a slight change is introduced ints the above process. The circumstance that the anti- mony, arsenic, tin, lead, &c., which exist as sulphides, quickly lose their sulphur, and are changed to a metallic condition, by coming iu contact with coppa or its oxides, causes these elements to be collected in the first copper that faiis as a metal to the bottom <rf the furnace. "\Vhen therefore these copper bottoms are tapped off — when but about one fourth of the matt is reduced — what remains in the furnace produces a nearly pure metal.

These bottoms sometimes contain as much as 12 to 14 per cent, of tin, and are worked up to form an inferior product known as tile copper. The scoria, which is called roaster slag, is very basic and rich iu <opper; it goes back to he reduced in process IV.

: Metallchgy 01

— BEFIN'INQ THE BLISIEa COPFEK AND POLING.

In this process, tlie smelter brings Lis metal to the mditioii of a marketable product. The copper result- Dg &om the last smelting, as baa already been shoTm, mtains several per cent, of various substances, such I enlpfanr, iron, lead, tin, antimony, &c., which it is le object of this operation to remove, and afterwards I produce in the purified copper that condition of olleability wliich is known as tough pitch. The for- ace employed is similar to that used in process II., iicept that it is smaller and has no hole in the hearth through which the contents may be tapped off; instead rfthiflarraugementjthe hearth is made to incline slightly Mward the front side, where a small depression is left liat collects the liquid metal, and allows it to be dipped at with a ladle. The charge, consisting of about eight )ii8 of blister or coarse copper, is deposited in the con- lition of ingots on the hearth, and the doors imme- Kately closed and luted fast. A strong heat is then iven and kept up, until the copper is completely melted, when the slight slag which collects on the arface of the metal bath is skimmed off, the draught Secreased, the apertures prepared for the admission of atmospheric air are opened, and the oxidising process ixnnmences. The metal is occasionally stirred with a rake hat the separation of the impurities may be more mplete ; and some refiners throw pieces of green wood la the surface, under the impression that it assists in , lie escape of the sulphur. The suboxide of copper is kmned in the upper stratum of the fused mass, a

Ui

TliB WrrAltTTBOT fK- 1

being solulilc by the melted metal is absorbed inti w}iere meeting witli easily oxidisable metals sue! iron or zinc, it givea up its oxygen to them ; wh upon, by reason of their lower specific gravity, 1 rise to tlie sarface, and, meeting with silica, they quickly turned into a slag, which is scraped off by attendant. Subsequently, sulphur is changed by same oxidising agent, to sulphurous acid, which aBO iug to the surface causes a boiling or rising is mass, but the attraction of the tin, arsenic, and i mony for the copper is so great, that but a small q' tity of these metals can be extracted in this man Some manufacturers add a little lead at this stag the process, which, conabining with a part of the i raony and tin, forma a heavy alloy, that falls to bottom of the hearth and can be separated. The is allowed to play over the surface of the metal some time after the boiling has ceased, until a sai taken from the furnace shows by its colour, frad and manner of cooling, that a large quantity of suboxide of copper remains dissolved, and hence refiner being convinced that iron, zinc, and sulphm expelled, proceeds to the last stage of the process— polinff.

The dry copper, as tJie metal having a large qu&i of suboxide in solution ia called, is first covered wi layer of powdered anthracite or of charcoal, for purpose of preventing the absorption of more ojg

The suboxide that remains dissolved, is now redi by thrusting within the fluid mass, a large spar or of green birch or oak, which is decomposed by the 1 heat ; carbonaceous gases are evolved, which esca through tlic metal, act strongly, reducing thenxie

by tlie commotion produced, cause every part to be aght rapidly and tlioroughly in contact with tlie bracite or charcoal on the surface, and ia this way lie suboxide may soon be reduced to metallic copper, le'its gaseous portion escapes in coiiibinatiou with )on into the air. This actiou is continued for from

ii'ter to half an hour, during which time samples tftVen at short intervals and tried beneath a hammer 1 a vice to determine their malleability. When the lal has reached what is termed the proper ticA, the bends readily without showing any breaks on the

I, and its fracture should have a fibrons silky lustre, 1 a light colour. When this pitch is attained, the S is withdrawn and a larger sample termed a trial, en out, and cast in a small mould, and is beaten 1 sledge-hammers into a plate. If the copper be i this plate will not crack on the edges, and the face will be smooth and free from scales. It occa- nally happens that poling is continued too long, in ich case all the suboxide is reduced, and the metal mnes a light colour, loses its toughness, and becomes rd. To remedy these defects, which ai'e variously Bribed to the absorption of carbon from the pole and s,'and to the action of the impurities in the metal, ich the presence of a small quantity of the suboxide copper neutralises, the air is again allowed to play irthesurfaceinorder to oxidise the carbon, or produce ire of the suboxide, and the operation of poling re- ited. When by the assay and trial the coj-'per is md to he neither insufficiently deoxidised [rf/'y] nor r-jioled, but to be of good colour, soft, malleable, I tenacious [tough pitch), it is laded from the furnace D moulds which form it into ingots, tiles, or wire-

iarv, m the demnnd may be. Wheii it is inteaded fil the DMnnfacture ©f , it is granolated by a p memblin that described for the granulstion c caane metaL When the water into which it ii is hot, ronnd grains are obtained analogous shot, xnd copper in this state is known as bean Wben the melted metal falls into cold water, the grasl are irregular and thin, constituting featfier am Copper is also made into small ingots about six onaMJ in veight ; tfaer are intended for exportation tO In But Indies, and are known in commerce as JapaM Co pper . These little pieces, as soon as solidified, n thrown in their heated conditiou into cold water, irfad slightly oxidises their sui&ce, and gives them a fiBeM

Copper is sampled for sale by drilling two h(deB fli opposite sides of the bar or ingot, and dividing M clips prodaced between the assayera of the buyer an the selier, from whose analyses the worth of the piodid is determined.

Chapter Xi.

Ths Sheltius o

The county of Maiisfeld, which lies just beyond m sooth-west borders of the Hartz, has long been cel(

Tbe desuiptioaa of tlie Miuisreld praBa, nliicli even to iritLin TCI Toeat dAU imie been pubIiBlic<l ia Ibe Eogtib language, will be Cmad iliflsr viitelj froia tbat givea bere. Tbej generally cibiliit the coniltli (if iha meUllnrgic proccseea as tbi>; exialed tbirtj yeara ago. tl d no method in onppei Emelting bna vuMd tbraogh a

I for its copper. Previous to the thirty years' ', much metnl wits BCut hence to the maDufactiuing of Europe, That coavulsion destroyed its lerity for a time, but about 1730 its mines and wes were again opened, and from that period until B present day, copper and silver have been produced I gradually increasing quantities, and new processes reduction have been successively invented and opted, and in their turn replaced by better, until, at , a degree of technical perfection has been uBed which leaves little to be desired.

,aiid iDatructlre series of pliiiseB, The ancient proceaa of liquation (see Iter rai.) was then in nae fur Eepanting the copper and silver, aai! the RM omeltings uiil rossliDgs bud the object oE pi-epnring the metal fiir Wiattfol operktiou. Ibis ceased entirely in 1836, ojid garo jdiLCe (o Imb BipenaiTe but nnbcalthj method of amalgamaling the eopper matt, b had long been in course of experiment at the companj'a works. I lonfinned until I S j9, vhea the iDgeuiDns pcocesH of AngiiEtin waa l(ed for a time. It wns in its tam replaced bf the simpler and po' plan of Zierrogel, which was invented in ISIO, Sind brought to a tdextentiutouEain 184J,aDdh>ia been since ISSlEiclnaiielyemplojed, In difference in the previoue and snlHieqiieut working of the eopper tnl mahea it diScoit to iustitnlo a BompuiEan of the expense of dmising h; the variauB plans, bat ranghij the cost of treatJn ndredweiglit of copper, which nannllf holdB J lb. of silver, w

Liquation 10 thalen.

Amalgaianiinn „

Auguatin'e method ... „ Ziei-Yogel'e method... sj „ jTini of silver remaining in the copper waa, by

Iiiijuatioo th of on<

Amnlgamation th ,

AugBfitia's method... jtli ,

ZiervDgel'a method ., . gth

I CHUiot fa.il here to enpresa my thanks for the kind attentions ai

! given me by tue very intelligent officare of the varioun mines, i and rulliag mills belDngiag to the Manafetd Company I Hettstedli ami Bothenbnrg.

TBE METAttWtOT Of i

The various mines and furnaces which wew

possessed by separate companies, were united ia under a siugle direction, the cliief ofSce of n1 situated in Eislebeu, and at present an ada system connects the various mines, furnaces, verisiog works, hammering establisliraents, and 3 mills, and profitable returns arc secured to the holders.

The ore occurs in a remarkable bituminous a( stratum ill the Zechstein, — a portion of the known to Eugliah geologists as the Permian, has already beeu shown to be distinguished for it ness in copper. It differs from most copper c being found not in a regular vein, but stratifii coal or slate whence is derived its usual name of schist. Regarding the manner in which thes were deposited or concentrated, geologists have given no satisfactory theory.

The mining, which ia soaietimea carried on depth of seventy or eighty fathoms, is partii arduous on account of the diminutive size of tl seam, the whole thickness of the stratum taki seldom amounting to more than eighteen inches, makes it necessary for the miner to do all hii while lying flat on his left side.

The portion which is smelted, constitutes bu 10 to 18 per cent, of this stratum ; and here the co chiefly contained as finely dissemiuated particles various sulphides. The following analysis by Bi gives the constituents with approximate accuracy

I JUETAIiUECV OF corrKii.

Bronght &rd GO '7 per cent.

OiWeofiran B-0 „

CarboDiteoflime ... I9'5 „ CarboniLte of magueBui 0-5 ,,

_Pot*8h 2-0 „

talphide of copper ... 6'0 „

WHeT and bitumen ... 10-3 ,,

proportiou of the silica to the eartlis is sucK s fusion is accomplished with little difficulty- tance of great weight in settling the economy iction. The proportion of copper in the ore letweeu 2i and 5, but will average in the neigh- jd of 2J- of one per cent., and the amount of resent averages not more than th of one per ir one pound of silver for £00 lbs. of copper. I these metals, zinc, lead, nickel, and cobalt

I the raw ore in small qnantitiea, and the win- f nickel vitriol is raade the subject of a special }n.

jugh the company possesses much woodland in nity of the Hartz, it is found more profitable to iir wood and charcoal, and hiing the chief part ' fuel from England, the German coal fields on the and various cities where large quantities of gas e made. Tlie English coke is considered of the iiperior quality, and it reaches the works of the ly in considerable quantities by way of Hamburg.

II bundles of brush wood or bushes r the muffie furnaces, and for calcining or and the brown coal dug in the vicinity s a cheap heating material when mixed with coals for the reverberatory furnace, and otfaec

jere a strong flame is recjuiTftd,

'ijnhere i

1 50 the' uSTAiixtici i

As flux, beside the mrions slags irliich I to be cast awav are returned to the tamfel ha Bpar is used where the ore is so silicioas a refractory. It is obtaiDed ia largt immediate Ticinity.

k

ICTUNE OP THE TKOCESSES iH DSE rOS SU AND DEStLVERlSIN-G THE MANSPELD QBE

In Btudyiog the series of processes which lea prodaction of the soluble metals the reader aided by keeping in iniud the following c auccesaion,

I, The burning of the schist in large heaps ' off water and bitumen and produce a me condition favourable for smelting.

II. The 6rst smelting in cupola furnaces, b the supei-ahuD dance of silica and earths are ren worthless clay, and a coarse metal or matt is p containing about 35 per cent, of copper with i the form of sulphides.

in. Boasting the matt or coarse metal in 1 the open air, for the purpose of driving off th abundance of sulphur and oxidising the iron.

IV. Concentration of the roasted coarse n reverberatory furnaces, nnd grauulation of the i pouring it into water. The result of this operal fine metal holding about 65 per cent, of copper an and a rich slag which is sent back to the first an

v. Grinding the granulated fine metal to a po

VI. Roasting the powdered metal until mos copper becomes an insoluble oxide, ajid all the changed to a aoluble sulphate.

XUE METALLOltOY OP

I VII. Disolviug out the sulphate of silter with warm and precipitattDg the metal with copper as

Mixing the remainder, which coutaitiB about

: cent, of copper, chiefly in the condition of ao

HadCj with fluxes and smelting it ju a cupolsi furnace,

>ducing lat a worthless skg, 2nd a rich matt which is

ait hack to the furuace, and 3rd a black or coarse

r containing 98-5 per cent, of that metal.

k IX. Refilling the coarse copper, which process is

r performed in a reverberatory furuace by a method

t does not difTer materially from that described in

pter X., tims producing a malleable copper at once

, the coarse copper, or according to the usual

ermao method, in what is knoivii as the German

earift, by which means rosette copper is produced,

Cliis product is either sold as such, or subjected to a

wnd process of refining upon a somewhat similar

irth, by which it is brought to a malleable couditioa.

P>Ail8 Of The Method Op Reducing Desilverising The Mansfeld Ores.

7I10Cebs I. — Burning The Ores.

The object sought to be accomplished by this process

H to get rid by volatilisation or eombustiou of as much

possible of the bitumen, water, arsenic and antimony,

1 a portion of the sulphur which are present iu the

I ore, and thus to produce a state of division or

vjooseness among the particles, that will make its fusion

t in the process immediately following. To drive

' too much sulphur is however disadvantageous j

noagh must always remain to produce a good coarsaj

metal. The process partakes more of the nature i burning than of a ronstingj and it is genei ftcconiptisheil in large heaps generally conatructec the immediate yicinity of, and on a higher level f the smelting furnace.

The ore delivered by wagons from the compa mines is weighed and deposited in the burning y When a heap is to be formed, a number of bundle dry brush wood are laid side by side on the paven where the borders of its foundation are intended tt thus enclosing a space 2 or 300 feet long, and 30 o broad. Across this space two or three rows of bun are laid, and another row in the direction of its Ion diameter, and where these interior rowa cross, 6 bundles are piled together. The schist is now broi in wheelbarrows, and piled loosely on these faggots i the heap reaches a height varying from 7 to 10 From 300 to 900 tons are then thrown together ant on fire at one side. The fire gradually spreads, rows of brush wood furnish canals by which air er the centre of the heap, the piles of wood along middle line act to a certain extent the part of chimi and the entire heap undergoes a slow smoulde combustion, "When the schist is heaped while moist condition it burns better than when it is used because when the water has evaporated the mai loose and permeable for the air. Such a conditio brought about most effectually when the heaps made during cold weather, so that frozen blocks ca piled together and subsequently allowed to I gradually. It is also mure than probable that yi takes an active chemical part in the combusl iVheo the fire consumes all the bitumeu in thegobi

TltE "mktjU.li.'bgi- of copfek. 1 53

tad the process is ended ; thia takes place m a It6r or less time according to the ate of the heap, t seldom in less than S or 10 weeks, and loinetimes r S or 4 months. The schist is cbanfed by the eration from a dark coal-like mass with a rilky Btre to a gray ashy sabstance, which does not in the ist resemble a metalliferous body. Sometimes where roDg winds prevail for a number of days, the ore lelts together and forms a solid mass that is difficult break apart, and "(which losing much of its sniphnr the high heat, has to he mixed with a highly Iphurised ore in the noit smelting. That this trouble ly be avoided the workmen often shelter the heaps from ic storm by boards, or a coating of small coal placed I the side from which the wind blows. Tlie loss in sight by the operation is about 16 per cent, lumc is made leas, and ahont 10 lbs. of wood i per ton of ore.

—THE PIBST f

The burnt schist is now carried from the burning to the furnace where it undergoes the first lelting. This process has for its object the con- otration of the valuable metals in a rich sulphide or e metal; and the production of a poor slag whiclr otains most of the siiica, lime, and earths, with which e ore ia so largely encumbered. It is accomplished in cupola furnace having the construction shown in the companying axinometric drawing (fig. U'). iu which t comer is represented as having been c!it away, It the interior arrangements may be lietter seen. the entire height of thia apparatus is

The Metallobgi Op Copper.

taches ; its greatest width at o, 5 feet € height of the hearth, g, is 4 feet 11 inches; aaS &om the bottom at c, are two taveres of cast i]

i iDtroduction of air. Tlie hearth -stone,

G inches wide, and slopes toward the front ride, lower portion of the furnace where the heat is sti is built of the red sandstone of the rieinity, w! found to withstand fire very well. The upper j above o is constructed of fire-brick, and the walls ai-c of common masonry. The blast empli heated to about 370" Fahrenheit, and is forced i a pressure equivalent to a column of water 1 inches high. In front of the fui-njice, hoUowei bed of a inixturo of clay and coke powder, ai I, ff. three feet in dvamelci; -Awi oa

THE METAIXtmo? CiP COPPKa.

wliich the elag ore aad coarse metal run. MiUer furnace is in use at some of the smelting works, tt its similarity to the ahove is so great that it does It require an especial description. The materials of the charge to be smelted are ftnsported to a floor near the tunnel-head, b, and iDEist in general of

SS-Bfl per Mnt roasted ore from operstion I. 6' „ Flnuispnr. e-8S „ Blag from operation IV.

The fuel employed is either English and Wei utlian coke, or gas coke; when the former is used, to 70 cubic feet are required per 100 civt. of roasted

; of the latter, SO to 90 cubic feet are necessary. 3 fuel is put on in layers with the ore and flux, and esh charge is always added when the gas at the lace top begins to burn, so that when the operation iroceeding properly, no flame issues from the upper 't of the furnace. The contents of the shaft sink

lually towards the tuyeres, Tiie metallic oxides in

ore are partly reduced by the carbonic oxide

ipUed by the fuel; the flnor spar is decoinpoaed, and

'olatile compoimd formed with the ailicum; while

lime together with the other bases, as the alumina I magnesia, combine with silica, forming a slag which VB continuously from one of the two openings at h, I hence into the basins,//.

Portions of the zinc and lead are reduced and Bitiliaed, being chiefly blown by the strong blast behind, in the foi-m of fumes out of the apertoiflftd producaag a long greeniak blaa ftame.

copper, silver, and some of the] iron smelt together ns n compound sulphide or coarse metal, and flow with the slag into the baains, // By reason of its greater specific gravity, this metal collects at the bottom of the basins, and the slag floats upon its surface. As the hoUons fill, the workmen drag away this slag which n tough and glassy, and remains soft for a long time. It is pressed into iron moulds and allowed to cool, after which it is sold to the neighbouring peasants for bnilding stone.

The basins, //, are used alternately; the coane metal which collects in them is allowed to cool in one, while the other is being filled, an operation requiring from S to 12 hours. The cooled mass' is drawn from the basin by means of an iron bar which is inserted in it while yet fluid, and broken in pieces with sledges. The rough exterior is sorted out and returned to the fusion just described, while the remainder, being about 10 per cent, of the quantity put into the furnace, anj consisting chiefly of copper, iron, silver, nickel, cohalt, and zinc with sulphur — the copper constituting from SO to 40 per cent., and the silver from t|- to -I- per cent, of the compound — is now passed to a yard near tiu furnace to undergo the next operation.

raocEss iii. — boasting the This is performed in the open air, in stalls 6 or 8 feet square, and capable of holding 200 to 3O0 cubic feet of coarse metal and fuel. These stalls are simply open pens of common masonry formed of three per manent walls, and a fourth composed of loose stones which may be taken down -vie-a. me'wi. w he

TiHE METAI.LITItGT OF COPPEI!.

Todnced or removed, but affords a pormeabte support the pile while combustion is going forward. A tion of the metal requires a repetition of the process roasting. For the first fire, the metal in pieces lUt a quarter of a pound in weight, is piled in the closure upou a layer of wood, that serves to kindle mass, which when once heated, continues to buru the consumption of its sulphur. To regulate the mission of air, a layer of breeze or coke powder, But 4- inches thick, is spread over the surface of the ftp.

When 20 tons are burned together, the combustion Dtiniies about 10 days, and a loss of sulphur and ler substances is experienced amounting to 12 or 13 r cent. When a second roasting ia required, the tall quantity of sulphur present maJtea a larger lount of fuel necessary. The roasted metal is piled smaller heaps, and for every 5 tons, 14 cubic feet of coal and 400 lbs. of wood are used. This second eration produces a mass rich in the oxides, and of a rk brown cellular appearance, which together with a (per quantity of the product of the first roasting,! subjected to process IV.

]

kOCESS IV. — SMELTING FOR CONCENTRATED MET,

Vbia Operation was formerly carried out in a cu] ace of a construction similar to that described re, but within the last ten years this has been tirely superseded by the English reverberatory smelt- f furnace, which was introduced by Hiittenmeister ttvogel from Swansea. A description of this furnace , I vireaciy been given in the chatev devoted ta

consideration of tLe EngUsli method of smelting copper,

and the cbangea tliat liave been introduced at Mani are so unessential, that a further detail is not requited.

The object of this smelting is to secure for the sub- sequent process of desilverisiug a moH or fine metal eiy rich in copper and silver, and to drive off the araeni lead and zinc that may be present, and if allowed to remain would interfere with the extraction of the silver and injui-e the quality of the copper produced.

TLe roasted coarse metal is wheeled to a large plat' form above the furnace, and there mixed as follows i—*

IS cwt. of coarse metal twice roasted. i

1 or more cwt. of coarse metal once roasted, AV quantity depending on the amount of sulphur required;

2 cwt, of slag from process II.

24- cwt. of quartz in the form of sand.

Thi3 mixture is thrown into the hopper on the top of the furnace, and by means of an iron sluice let tfarougli an aperture in the vault once every eight or nine boun. The workman spreads the charge over the surface of the hearth with a long iron rake ; a strong fire is then made, and smelting seta in. At the end of 7 or 8 honr the contents of the fiuTiace are in a fluid condition, the silica has combined with the oxide of iron and the earths, and swims upon the surface of a thin stratum ef matt, ivhich consists of the sulphides of copper and silver. Tliis alag is scraped off at a side door, and ft new charge let down upon the hearth, smelted as before and the slag drawn off. These smeltings require 16 OF 17 hours, at the end of wliich time a large quantity of matt has collected in the bottom of the furnace.

A clay plug is now broken from an aperture in oos side of the Learth, and the ma.tt aWo'NcA \.i'

; STJiLCBST OF corrEii.

fc into a trough containing water, irliere r into small drops or grains and fulls to t n ; when shoTeled from this lat and dried, ij to be sent to the mill to be ground to a powdei lag that is drawn from the surface of the mat ins some copper, and is carried hack to process I] ! it is mixed with the burnt ore aud again smelte iiel employed is a mixture of Enghsh coal and i f brown coal which is found in abundance in tl ty, iu the proportion of il of the former to 16 tter. By means of an inclined slair grate reeentl; iuced, the proportion of the cheaper brown can he used is increased to Zi parts to 11 sh coal.

Cess T, Orixding The Concentrated Metal.

B object of grinding is to bring the concentrate , to the state of a fine powder, that during th Following operation, upon the success of which

depends, the greatest degree of uniformity n icured in the chemical combinations that : [bt about upon the roasting Iiearth. The granfl metal is treated nearly as corn in ordinary milk )assed through horizontal burra 4 feet in diameta

of the granite of the Hai-tz, and driven by ti r. Upon passing through the stones tfce roug) er ia conducted to be bolted, into a hollM irical sieve having 1400 to 1500 apertures i ijuare inch, and ail the powder that will not pal igh this is sent back to the hopper to receive ;d grinding. The meal produced by tins operatio I from the various smaller eatahUahmenl

tated fro.

and tmnsported to the GottesbclohTiiiog furnace, when! the entrnction of the silver is exclusively performed.

— Roasting The Powdered Concentrateii

{ZiervogeVs method of exlracting silver by meant of warm waler.)

Tlie foregoing operations have constantly teniw toward a concentration of copper and silver, wlu(|) exists disseminated through the poor schists, into B- single product. In accomplisliing this the attractiffli' poaseaaed by copper for sulphur lias been continuiilly talten advantage of, until at this stage of the process a sulphide known as concentrated metnl is obtained, wbieli in 1S60 contained 67-512 per cent, of copper, 0-3531 per cent, of silver, and 6 or 7 per cent, of iron ; or to the hundredweight of pure copper 0.5215 pounds ot silver were present. This matt is now at the prop degree of richness to subject it to the process of extracting the silver by what is known as Ziervogeft Method, and the present roasting is preliminsrv operation in the extraction.

The essential condition upon which the success of separating tlie two metals rests, is simply the transfoN mation of the silver as completely aa possible into a soluble vitriol or sulphate, while at the same time the copper and other metals are made to take on the condition of insoluble oxides.

This can be done by very carefully roasting the powdered concentrated metal or sulphide in fumaoet especially adapted to the puipoae. TKe cottstTuction of

it 15 feet; the two LeartLs a and b upon which roasting is performed, are 10 feet long and S feet A, and are formed of good fire brick, which material 10 used for the construction of the chimney and all I parts as are much exposed to heat. The fire is e upon the grate through the door e, and the flames ing across a firebridge play over the contents of the th B, and going up the flue r, are canied a number back and forth through the canals q g, where

Uie Email particles of ore tliat become cntaagled in ihti drauglit arc deposited as a very 6ne powder, and Bubaequently collected and carried to the smelliiif furnace to be fused for the copper and silver they contain. From this series of cauala the gases escape through the chimney H into the open air; the hearth k is entirely heated by the flames circulating below and above it, being to all effects a. muiSe, and bence weB adapted for the purpose to which it is devoted, that o£ beating tbe minerEil before it can be brought to a temperature, without danger of fusing. Between hearth and that below, a bole j, closed by an plate, permits the shiiling of the charge, and anotiHE aperture at k allows tbe finished mineral to be scrapfl by means of a long hoe working ovef the roller v, itio an iron waggon that is placed in the vault i.

Tbe powdered matt as brought from tbe miUfia mixed with about 15 per cent, of the remainder lixiviation in process VII., and to the amount of 500 or 600 pounds placed upon tbe upper hearth a, and there exposed to a graduaUy increasing temperature; thii charge is stirred for about 1-f hours, and then the portion of tbe powder in the binder part of tbe furnace is brought forward neai- tbe fii'e, the small lumps tbt are formed are broken by beating tbera with an il0 rod and the stirriug continued If hour longer. Thn an addition of from 20 to S5 pounds of dry brown ooA powder is made to the hot metal, and after 10 minutei stirring the entire charge is scraped through the aperture, and spread equally upon the lower bearth B. The heat is at first allowed to be moderate, but after hour stirring, during which the brown coal powder ia consumeil and a cherry red bea.t is arrived at, the

ttit MttrMtuiidT oy COPPER.

Ige is turned in the furnace and tlie heat gmdi cased.

E the end of 10 or 11 hours from the commci It of the roaating, the workman, wlio has stii teatly during the latter part of the period, begins pake his tests for the purpose of determining if Iroastiug has progressed to the proper point. lis done by drawing from the hearth a spoonful of Hiot powder, placing it upon a common saucer, niing water upon it, and allowing the Suid to filter ly through. The water takes up the soluble salts i may be in the assay, and from the colour the kion assumes, a good judgment can be formed ecmditioa of the charge. When slightly blue, lin the least green, and when a few grains

ron salt dropped into the solution throws down white curdy precipitate of chloride of silver, the ling is considered accomplished, and the charge is in out and transported to the magazine. The loyed is brushwood, which makes a sharp and et voUable fire.

I this process the chemical changes that go for' I interesting, important, aud complicated. The per, silver, and ii-ou which exist in the matt as

rdes, act differently wheu exposed to an osidising The iron loses its sulphur, becomes a sulphate, then au oidde, in which state it is insoluble irater : the copper goes through the same series phanges, aud the sulphide of silver changes into ulphate, then into an oxide, and as the heat lontinued, into a metallic condition. The opera- 1 should, however, not be permitted to continue

tne

the irge is

The skill of tlie roaster consists in being able to Cft the charge just at the moment when the copper chi* ceases to be a soluble vitriol and lias gone oyer ii the form of aii oxide, and as much aa possible of I siWer is in the condition of sulphate, and before i unstable salt has been decomposed, and the nl' assumed a metallic form. If the roasting is Etop[ before it lias reached this desired point, much cop| is left soluble and is carried ofT in the water, wl some of the silver may remain insoluble as a sulplui and cannot be extracted with water ; and on the otl hand, if carried a minute too far, nietalHc silvef formed which, being entirely insoluble in the m process, is left and lost in the copper. Long and much observation are required to train workn: for this process, and a scale of premiums have bi contrived (see nest section), by which good work rewarded.

The plan of this system of extraction has remait unchanged almost since its earliest adoption, but value has largely increased within the last few yei an improvement to be traced to the increasing t of the workmen, who are urged by the hope of rcw( 1 to make themselves complete masters of tlieir busint

Kiien'OjjeVs method of extracting silver by means

I The roasted concentrated metal which is now in

I form of a dark, loose powder, after having C<H tauMcientlj in the magazine, is transported to

iB VII. — niSSOLVINO THE SULPHATG Ot SIP FBOM THE KOASTED CONCENTRATED METAL,

THBT METiliEUHGT W COWftlft.'

rtment devoted to lixination ; this is a large roc

ig a series of vessels arrauged uiiD the accompan}!

Irawing.

wooden vessels, a b c u and e are so placed thii

liquor flowiug &oui one may run into the i

md s are tuba having double bottoms so arrangt

. linen-cloth liltcrs that only solutions are allowi

s from one to the othor. The roasted powder is ed, to the amount of 4 cwt. in the tubs a, (of (h there are 10), and water and liquor from I operations heated by steam to about 160° are ired to flow from the pipes i and k. This fluid aeatea the ore in a, takes up the soluble salts, the t important of which is the sulphate of silver, and 3 it, in solution, into the vat b, where it is allowed Bttle. Prom tiiia it floiva into the tub c, which is rlded with 10 lbs. of granulated cop]>erj and cwt. blistered copper bars ; here, on account of the xo-negative cliaractct of the silver when comiared

Ibs

THE HETALI.tniCiY OF COPTfiK

with copper, it is precipitated in a. metallic conditi centent silver. The fourth series of vessels repres by D, also contain copper, and is simply used security against any loss that might occur by al silver not being precipitated in c. Prom b, the falls into the wooden vat, e, whence it is rai stenm pressure, to a higher level, heated to 160' passed over a new charge which, iu the tneantii introduced into the tub, a. An addition of abi cubic feet of fresh water is required for each cl which is furnished by the pipe ;', while about 22 feet of liquor arc run on through the pipe k, and i same time a small quantity of sulphuric acid is i to prevent the disadviintageous influence of basic About 24 hours are required to dissolve out the from each charge of ore; at the end of this tini contents of the tub are transported to an adjc room, an assay taken, and a new charge is plac the tub, which is treated precisely iu the mannei described. This assay proves the excellence roasting j when 0-036 of one per cent, or leas rei in the powder, the work is deemed good, and it ] to operation VIII. "When, however, more is foun powder is sent again to be roasted,— the wor having to attend it without pay. If less than 0-C one per cent, of silver is found present, 12 per ce the quantity leas than that amount goes to the ' man who roasted it. The advantages of this syat premiums hav£ already been spoken of.

All ores are, however, not adapted to this metl separation; when antimony and arsenic are preae large quantities, the insoluble arseniates and Oniatea are formed during roasting, and 1

*HB WerSBjtfBQY OP COPPEH.

icted by hot water. The plan was tiicd in tl berg silver irorka, and it was found that, on account le presence, to a considerable amount, of the two e-uamed substances, there was invariably — even

tke most careM roasting, — about 0-15 of one

of silver that remained in the copper. [le silver falls almost entirely in the tub, c,

it is taken at proper intervals, and brought to a lition fit for sale. Its most important impurities sulphate of lime, copper in the form of sulphate in grains, all of which amount to about 20 per The first two are dissolved out by repeated lings ; the last is partly taken out by passing vi acid over the finely-divided metal. This is ted in a peculiarly constructed furnace, where it [ght to a fineness of ,",1 , — the two per cent,

ity being copper. This silver is bought by the tinBerUnj and the copper is not considered dis-

itftgeous, since it is allowed to form a portion iiloy required for silver coins.

even

PIlOCESB Till. — FUSION FOB BLISTEK COPPER.

m

the lis.

! remainder from the lixiviatton tubs that i I by careful assays to contain less than 0'O36 per of silver, is now ready for making into blister

fer, This is done in a cupola furnace constructed tially on the same plan aa that which has already described for carrying out process IL, but differ-

BOmewLat in its various dimensions. The lixiviated ier, which contains 70 to 75 per cent, of copper,

Ay as an oxide, and some oxide of iron, is mixed 8 per cent, of a clay containing 50 to 60 er fl

of silica, and 40 to 50 per ceut. of alumina, worked lay liaiid into balls about 4 inches iu diameter, and dried until hai'd. Ttiis admisture of clay has the daublft purpose of furuishing a source of silica for the slag an! the formation of the powder into lumps which will not clog the furnace. On the floor nt the tunnel-head luf. addition of about 9 per ceut. of sand, 5 per cent of pyrites, or gypsum, 1 to 1 5 per cent, of slag from tliii or process IX. ; and 1 to 2 per cent, of matt from tbi| process, ia made, and the mixture placed iu layers the furuace with the fuel, which cousiata chiefly o( English or gas coke. Coltl air is employed, and about 150 cubic feet are forced in per minute, under S pressui'C of one inch of mercury.

The arsenic that may by chauce he present is driTeit> off in the hot upper part of the furnace; a httle lom' down, the silica of the clay and sand combines with tte oxide of iron forming a slug ; a greater part of tfce copper is reduced to a metallic condition, hy tl chemical action of the carbonic oxide gas, and the sulphur furnished by the gypsum and pyrites, serves to clear the slag of its copper, thus formipg a rich matti These are the three products that run continually from the two openings at the lowermost portion of the furnace, and fall directly into a basin in the liratque hearth, where they divide themselyes according to theit ral specific gravities. The slag, which rises to th top, amounts to about 30 per ceut. of the entire result of smeltiug, and is dragged off in disks, allowed to cool, broken and sorted, and the pieces containing matt are returned again to the furuace, while tliat which analysis shows to contain J per cent, of copper or less IS thrown away.

TBS METAtttmOt OP COPPER.

Icij

! second product the rich matt, composes about : cent, of the entire fall from the furnace, and

s a thin layer between the slag and blister copper.

i back to the tuunel-head immediately, to be

I with the charge. The blister copper forming

r cent, of the results of smelting, collects at the

the basin in a dirty, tough, often cellular

i per cent, of which is pure copper, and ia

ince to the magazine, and afterwards to the

unace, where it undergoes the process

ICE88 IX, — PUniFTING AVI) REFINING THE BLISTEK COPPER.

rhe copper produced by the Mansfeld Works is iyered to manufacturers in two forms ; as rosettt ; or thin round disks adapted for casting, and the king of alloys, but not sufficiently malleable for nmering or rolling ; and aa refined or poled copper ich is sold in the form of ingots or bars, and leesees, like the best classes of English copper, the iperty of malleability in a high degree. Purifying the blister copper for the formation of ettes, is a process pecuhar to what ia known as the itinental method. It takes place in an apparatus led the Small German Hearth, which has already m mentioned in Chapter VIII. The basin. A, is med in a mass composed of 1 part sand, 4 parts clay, i 4 parts of charcoal powder, and is large enough to Id 5 cwt. of metal. This amount of blister copper is ced in it and surrounded by charcoal, which is soon to a state of rapid combustion by a blast of utffl

of silica, iu.ll

/if, i/. T-i nojile:

a, of 1')' into the hamt

' until hitni.

ff Ht the ntooth. H

1 purpose of i

the formal 1.

dog the f.i

additiou i.i

pyritc., ..,

of proct-j

procee.,

the fun

Engli.1,

1 160 ,

nl crate quantity of HB|

press,

, and tlie impuritiea sua . ,;ntimony, and sulphur, b(

off ii

-iii' influence, are turned

dow,

ri.maininrf at the end of

' copp,

; ,„™, i, nearly pure, o.

che.

iMii:iiderable amount of

. ct-ii is largely soluble ii

cleB'

.i;' contents of the heartl

( The,

.Kidirion which ia indicate

the

.'I' liio scoria, the colour ol

fun.

. liiiipei'tiea of a test taken

Ilea,

.1 ol' an iron bai-— the fn . .. :ui surface of the metal et Jtgau. it. The crust thus for is inches iu diameter, is take and a second thin disk form

Md

Thus the whole of the me)

lM!rtli, which may then be re|

E

Yrtse rosettes mc 'iawiActed

1 METAIiURGT OP COPPEE.

I quite thin, moderately smooth, Jind of S red colour; they are now packed in barrel I ready for market,

1 16 to 17 per cent, of a rich red slag falls by tbii in ; it holds much nickel wliich is obtained from lubeequent processes, some of which are kept

jortion of copper that is refined or brouglit to known in Wales as the " tough pitch," is treated Aeratory furnaces, and by a plan which so nearly lea that described in the foregoing chapter that; t necessary to detail it here.

long series of years since the beginning.

in Mansfeld, which have been well used Qg experience, the unique regularity of th6 IS deposit, and the almost unvarying composition ores, have produced in all the operations of the there in operation a raachine-like regularity, B as extraordinary aa it is admirable, stimate is made at the beginning of each year of t, to the -J of a farthing, of all the items iture which will be required to produce the fixetf r of pounds of copper, silver, lead and nicke}„ e result of the year's work seldom shows

variation from the dcteiinined sum.

following statistics will give a notion of th*

ince of the company, and the amonnt ef

858 were directly dependent on the Coppe?

and Smelting Company at Mansfeld ;

THE iisTisijmiSY OP coppbb.

FcnnTu empldjcd in and ribont the mir

Smeltera, coltiera, anil macbiiUBta

Families of tile aboya

AeaiBted and sDppor(d lM

In the same year were rajsed, 111,920 cwtJ cost of 79,947/., and the following products wel

20,072 owt. of copper

13,385 Ilia, of fiooBilyar

2,0fii owt of copper ritriol ..

irieirt. of Itad

13,650 lbs. ofnlolieiapoiao .. lbs, (f Yunadiii

Chapter Xii.

The Smelttns ov Naiith Coppei it Detroit in thb Ubt

The process of rainiDg and dressing the ns copper which is found on the southern shore of I Superior, in the United States, has already I desci-ibed in Chapter V. This product iu its var forms as tuass copper, barrel leork or stamp tear transported hy lake, river, and railway to Det Cleaveland, and Pittsburg, to be smelted. The ad' tage secured by this transport, is found in the circ stance that the metal can be reduced in the injmed vicinity of the vast coal deposits of Ohio and Pent vania, and fuel can hence be obtained at the work large quantities at a low price. Within a short 1 past, however, an establishment has been put in op iion in the copper region, oa "Can a\te q£ au ol

Bruce mine. It is supplied mtli fuel, brought

load by vessels tbat carry ore and metal

ito the coal regions near Lake Eric. Beside

lere are three furnaces in the Union, located

iTely at Baltimore, Boston and New Haven, that

It the produce of the Lake Superior as well as other

mines, and also import ores from South

tuericH, the Pacific islands, and other parts of the

vld.

The establishment at Baltimore is operated upon a stem not suffering very widely from that already miHar to the reader as the English met/iod. The nildings are situated upon the shore of the eom- lodioua harbour, and beside ores produced iu the leighboui-iug states, large quantities are brought in ly homeward-bound vessels from copper regions in le southern hemisphere. The fuel used is mined . the coal fields of the AUcghanys, and the amount saleable metal produced annually is given at 100 tons.

The ores reduced at Boston are obtained partly from ines in New York and the Eastern States, and largely, is the case at Baltimore, from ports on the Pacific cean, whence they arc brought by returning vessels tis illast, and delivered at the furnace at prices often oite favourable for the smelter. The nature of these iB is as various as that of those sold at the ticketings Swansea ; the carbonates, the sulphides, the silicate ad arseniates are abundant ; but the gray copper ores re nre. The quantity of ore smelted in 1854 was miewhat over 10,000 tons, the amount of metal in hich, averaged 20 per cent. The system of smelting i somewhat similar to tbat known as the coniiaental

method, and consists of a roasting, as at Mansf ia the open nir, and fusion in low cupola furnaaa combined witli a subsequent re&niug in a rcverberiitail furnace, as is the custoni at Swajisea. The TesilH Bfrived at by this scheme of reduction, when conaideRB in an economical point of view, are deemed by Rivotn be exceedingly favourable.

TliK MMEI.TJNG WORKS AT DETJIOIT.

This establishment is favourably situated upon th abort river connecting Lake Huron with Lake &ift Its wharves are accessible to the steam and sail that navigate those waters ; and the heavy native OM shipped from the mines of northern Michigan, can 1)8 unloaded in tlie immediate vicinity of the fiimac where they are to be fused. The coal used as fuel, and the moat important furnace materials, are transported from Ofiio and Pennsylvania by the same cheap meuu of conveyance, and the copper produced has a COH- venient outlet to New York, Boston, and Philadelphu by way of lake, canal, and railway. The ores that an smelted are the property of various mines, and an simply brought to the condition of marketable coppa by the establishment iu consideration of a certain sua per ton, au arrangement which makes it necessary the mineral owned by the various mines be kept apt during the course of metallurgic operations.

The three classes of ores have already been stated to to be mass copper, barrel work, and stamp work. Th6 first generally contains many fragments or nodules of vein-stone that fill irregularities in the exterior of the block or are entireAy emVieAAci Kv Wa waM

il. It is evident that on account of these pe( ties uo accurate assay of the ore ciiu be made, and Tfisult on the smelters books is, in fuet, the only itiaa by which the per-centage of metal in the ika can be ascertained. The second class is often net free from foreign admixtures, bnt it doeti not such large quantities as the first, while the ip work is often contaminated to tlie amount of 50 cent, vith quartz, cidorite, trap, carbonate of lime, The severity of the winter causes navigation to be bstructed that ore can only he transported during Reason between May aud December ; and hence in 'ninter, smelting ceases, furnaces are repaired, and )aratioD3 are made for the operations of the suc-

' The Process.

poxe character of the ores produced by the Lake lerior mines allows the application of an extremely system of reduction, which may he conveniently ded into two processes : —

. fSimon of the native metal in reverl/eratory fur- is, producing, 1st, rich slags which pass to process and 2nd, a copper that is purified and refined in the B furnace in which it is first smelted, and when ly is caat into ingots suitable for sale. [. The Fusion of rich slags in cupola furnaces pro- isg 1st, a poor slag that is cast away, and i2nd, a we copper rich in iron, which goes hack to proows D be purified.

: Metallurgy Of Coppeb.

Fbocess I. — Fdsion Of The Native Metal I Bevebbebatory F0Rnaces.

The furnace here in use resembles somewhat represented by fig. 15. The hearth is about ]1 long and 10 feet broad, nearly elliptical in form, having a slight inclination toward the tapping near which is a depression where the fased a collects. This hearth is very thick and solid, and composed of various layers of firmly stamped broken biick and clay, and being over 3 feet thick partly fused together is impervious to the fluid resting upon it. The vault that is sprung over liearth is very low and instead of being supplied fig, 15, with hoppers, has near its middle a \ui quadrilateral opening that serves for the admission (t the huge blocks of native metal, and which is capable tS being closed by a plate of fire-clay strengthened iron. The two doors on the sides of the fumaOB through which the workmen stir the cliai-ge and remove the slag, may be closed in the same manner, all parts of the apparatus exposed to high heat are con- structed of refractory fire-brick, and the whole IB strongly cramped together with iron bars.

The operation of producing malleable copper in this furnace may be divided into three stages : —

a. Fusing, b. Purifying, c. Refining.

a. Fusing. — The masses of native metal, weighing occasionally as much as 4000 or 5000 pounds, are landed by means of cranes from the ships, and being carried to tlie furnace, are lowered by the same mechanical contrivance through the (quadrilateral aper*

; METALLOBGT OF OOrPEH.

re in the vault, and deposited carefully upon the birth. After a charge (which usually amounts to for 5 tons) is put in, all the apertures are closed, and Sre made by dUing the tire-place with coal, Hoirmg but little air to pass through the grate. is thus secured which is slightly oxidising at we-bridge, but which becomes reducing near the He. The large hloclis become fluid gradually, and, Wing to the bottom of the surface, are immediately vered by a slag of fused silicates, which protects the Rtal from the chemical action of the flames, The Bmplete fusion of the masses requires from twelve to Been hours, according to their size ; and after it is lUined, the heat is still coutinued for an hour, that Be particles of copper mingled with the slag may have be to separate and fall to the bottom. The slag is fen taken off by scraping it from the surface of the Ktal ; it is allowed to fall upon the floor, and wliile 11 hot is transported to the -vicinity of the cupola Etnaces, where it is drenched with water, that it may B more easily broken to pieces and prepared for the Bst smelting.

iThis slag is a silicate of copper, iron, lime, alumina, K; and holds from S to'lO per cent, of the first-named ftetal, as a suboxide and in disseminated granules. I b. PuHiFviNG.— The copper remainiog in the furnaces I now ready for purifying, which is a process resem- Bing that performed in the latter part of the English bethod, and consists simply in oxidising out certain, lipurities that may he still mixed with the fluid metal. Rie fire is made loose, and a large amount of air Bowed to enter the furnace. The substances to ba RDored become oxidised, rise to the suiCsce, and %

17B The Metaixuksy Of Copper.

takcu nway, aud the operation, ou account of the cot paratiTC purity of the metal, does not last more thi about half an hour.

c. Risi'iNiNo. — The attendant being convinced, i various assays taken from the furnace, that a lar{ quantity of the suboxide of copper has been absorlx by the fluid metal, proceeds now to the refining. ; new tire is made, and the air regulated so that tl flame becomes as slightly oxidising as possible. shovelful of L-hnrcoal ia then thrown upon the metatl surface, and a pole of green wood thrust into the flni and allowed to remain as long aa a atrong developmo of gas takes place. Assays are now taken to Indies the malleability of the copper, which, when phable at tough, is protected from further action of the air, 1 having more charcoal thrown upon it, and is thl dipped with ladles from the furnace, and cast into in moulds. "When the metal has slightly cooled, the moulds arc reversed, aud the ingot falls into a troi of water that is placed below.

The time required for smeltiuf;, reflniug, and castiJ a charge, is usually tweuty-four hours ; and with tM coppei' the amount of metal obtained is generally 75 p cent., or more, of the entire" quantity put into ti furnace. The barrel work is reduced iu larger charg) and forty-eight hours are often required to complc the process, The slump work is usually smelt in heats of two charges, each consisting of 3 toi ,the slag being drawn after the complete fusion of t first, and the second then addeil. The copper, whi amounts to 50 per cent, of the charge, ia removed fire the furnace at the end of twenty-four hours.

THE MtlTALLOKGY OF COPPER.

PHOCESS ir.-

Redoction Op The F Cupola Furnaces.

The object of thia fusion is to extract and secure tlie iper that is disseminated through the slags which 1 at the reverberatory furnace, aud thus produce ; poor enough to be thrown away. The operation is formed iu a cupola fui'nace, remarkable for its iplicity and efficacy. It is cylindric in form, about I feet high aud 3 feet in diameter, and is composed of angle thickness of fire-brick, supported on the ex- aor by a tirm irou-plate mantle. The whole appa- iDs is elevated about 3 feet from the surface of the rth upon pillars, and the blast which is introduced tough three tuyeres, that penetrate the shaft 1 foot the bottom, is forced in in large quantities with a of inches of quicksilver. Tlie lower end of B fiimace is steeply inclined towards the front side, lere an eye, or small opening, allows the metal and Ig, when fused, to flow out.

A- chaise of charcoal is then put into the apparatus, d when a proper temperature has been reached, the g and anthracite coal arc given iu alternatiug layers. te eye is closed until the fused mass at the bottom Host reaches the tuyeres, when the clay plug is oken, and the metal and slag are allowed to flow a basin in the furnace floor. Here the impure pper takes the lowermost level, aud the slag floating the top hardens, is broken, sorted, the portion free m globules of metal thrown into the lake, and the paindci returned to undergo another fusion. The true copper, which amounts to nearly 10 ijer cent,jj

tlie clinrgc, coatains about 8 per cent, of iron, and ii aeut back to the reverberatory furnace to be puri." The entire cost of smelting one ton of metal is rec' at dl. liin. wiieii made fi'om mass copper, and at 7 when stamp work is employed,

CHAPTER Xni.

EeBDIIION of CoPPKB by IDE "WBT Wll," JBD TARIOVS OMO

Agricola, whose work on minerals was published 1546, tells of a peculiar water which ia drawn fimi shaft near Schmiilnitz in Hungary, that erodes and turns it into copper; and in a curious work piw; lished in Venice in 15S4, two Hungarian riyuleti mentioned, in which by repeatedly placing iron it became "Cyprian" copper. These are the eailieii notices I have met with regarding the reduction o copper by the wet way, which is now practised, ffitli- niany modifications, in various parts of the globe. Ai a general rule, this method of reduction consists in throwing down the copper from its solution, as a stiW phate, in water, by bringing the fluid in contact irili pieces of wrought or cast-iron, which latter metali taking the sulphuric acid from the copper, goes into solution as a sulphate. The copper thus obtained, which is a crystalline powder, more or less pure, ai the solution may have been, is dried, fused, and reflued, in the_ usual manner. The application of the " wet way," however, is only found profitable under certain ciiviiBistitace6f — where £ueV is , 'nWxi ote* have a

\oiT per-ceutage of metal or a peculiar chemical podtioD, or where copper occurs in nature us a Ealt idy diaaolved in water. In all caes, however, in ;ing on a large scale, the metal must be submitti le or more fusions before it is brought to a mal condition.

Sod Of Extbactinb Copper Prou Fook Ores Usb Near Linz Os The Rhine.

lie Star furnace in which the following processes are ied out, is located about a mile from the left bank he Rhine near the town of Linz, The ores reduced brought fi'om several mines in the neighbourhood, 1 a number in the district of Siegen, and from the on bordering on both sides of the river. Mb ore is divided into three classes each of which ibjected to a special process; Ist, l/ie poor sulphides. the oxides, and 3rd, the rich sulphides which are need entirely by the dry way.

TIte poor sulphides, holding an average of 2 to per cent, of metal are roasted very cheaply and con- .ently in a kind of cupola furnace 10 feet high, ular, and 3 feet in greatest diameter. This furnace a operation is full of ore and fuel, which are ied in alternate layers at the top, and which sink ning to the lower part where the mass arrives lost freed from its sulphur, and is drawn by the mdant from a suitable aperture left for the purpose. len taken out it has a dark gray colour, but on DUnt of its highly silicious character, is seldom Lnged by fusion. It is then crushed between iron lera and brought to the condition of a coarse powder, j

lowder,

in urder tlint it may be more easily and complete acUitl upoa I>y the acid in the next process. Proni (h rollers the ore is thrown into mason-work basinit feet square, and 5 feet deep, having a false bottco formed of two horizontal layers of natural baultl columns placed at right angles to each other, the Ion series resting upon stone pillars one foot high. Ths vata are now ready for the introduction of the gases th*i are to bring about the solution of the copper; thetf are produced in the following manner : — Zinc blendf is chosen as a cheap material for furnishing sulphUTj it is first slightly roasted, that it may be easily crasbed and then brought as a powder upon tho hearth of i large retort furnace, and raised to a high heat i certain quantity of air is forced at the same time intB the retorts to furnish oxygen for the conversion of the sulphur into sulphurous acid gas. This goes off through a chimney to the above described vats, being on its way mixed with steam at a low tension, from a kettle heated by the same fire that roasts the blende. The mixed gases enter the space beneath the crushed ore, and, passing through the apertiu-es in the basaUio bottom, penetrate every part of the mass, and coming in contact with the oxides of copper and other metsls, formed from the sulphides by the process of roasting, oxygen is absorbed and soluble sulphates are produced and fall in solution to the bottom of the vat. From this the fluid is pumped and thrown into receiving vessels foj-med of wood lnult firmly in clay, and while yet hot is brought in contact with bars and scraps of wrought and cast iron, and the copper is thrown down as cement copper, while the iron goes into solution in its stead. The finely divided metal is wasted, to fre it

I ajETAIiLURGY OP

1 iron aud other impurities, and tlieu hmed in the 1 manner and reJined lathe German lieartli, fig. 19. The remains of the zinc blende left In the retorts e smelted by another company for the metal it mtaiiis. The roasted miisa has an average of 31 per int. of pure ziuc.

The liquor remaining in the vats after the precipita- on of the copper is conducted into broad evaporating BBS and brought to a high degree of concentration, nd then run into receivers where, upon cooling, a large mount of the sulphate of iron (copperas) is obtained y crystallisation. The mother liquor which remains after the crystals iave ceased forming, is made useful in another process, B will he presently shown.

2ud. The poor oxides contain, on aa average, not net one per cent, of pure copper, which exists prin ipally as a malachite or blue carbonate. The metal 1 also extracted by the " wet wiiy," but by another ilan. Instead of sulphuric acid being used aa in the oregoing case, hydrochloric (muriatic) acid which is ibtained from a neighbouring soda manufactory at S. 4rf. per cwt. is employed as a solvent. The ores lire broken to pieces and placed without further prepa- ation, in large wooden vats. Weak hydrochloric acid t the common temperature is then poured in until mineral is covered, and action is allowed to continue Inring ten days. The carbonates are easy to dissolve, ud they go over into the fluid aa chloride of copper. !luB solution is then drawn olf into precipitation vata, he metal precipitated by means of iron, and tbej

: copper thus obtained melted and reflned a be jsreraouslj mentioned in&tauce. In thiswajr-

]8i THE kETAiiciar or coppeil

the copper in the ore is extraeted, tiie small remaioiag existing probaby in the form of aa nrseninte. Tliis method is remarkitbly ecoiiG RCCOODt of the estrenie sioiplicity of the . required, and the fact that the espenditure i not necessary to insure its success.

Another plan for extracting the copper Iram oxidised ores is ia use at the Star furnace. In case, the mother liquor, or the fluid remaiuing after

iron vitriol has crystallised out, as described in the f

mentioned process, is used instead of hydrochloric aoi as a solvent. The ore in the condition of a tine powdi is placed in vats, each holding aliout ten tons, and liquor pumped from the crystallising vessels upon and allowed to act fourteen days. This fluid holds olation beside some free sulphuric acid, the sulphatffl of iron and alumina, which decompose upon coming a contact with the carbonate of copper, and the solublfr sulphate of copper is the result on one side, and the insoluble hydrates of the sesquioxides of iron an& alumina on the other. The copper in solution, miied with much sulphate of iron, ia drawn ofl' into another Tat and thrown down aa cement copper, exclusively witli wrought iron, since in such a weak and nearly neutral solution of the sulphate of copper, cast-iron would have but a slight action. The cement copper is made mar- ketable by the usual process of fusion and refining.

TUE ritOCESB (

BECCHI AND HADPl M4SSA IN TUSCANY,

This process, which is the invention of the two above-

eutJcmen, ia in opevRtiun u'o. ;

! MBTAlitmOY OP COPPEE.

la, in the southern part of Tuscany. The ( are extremely poor, having an average of only per cent, of copper, which is disseminated as ET pyrites through a large vein of nearly pure %z. The ore is hrolcen into pieces, not exceeding [inches in diameter and piled in alternating layers wood, in heaps of 200 to 350 tons. This roasting- tiished in ten or fifteen days, and serves chiefly to b the ore friable, that it may be easily crushed Hth revolving stones that prepare it for the second Sng iu reverberatory furnaces. The powdered ore K removed to the sole of a reverberatory furnace, ia led to a high heat, when two to eight per cent, wding to the amount of copper present) of common introduced, and after ten minutes' continued bg, the charge is drawn out. This introduction

iloride of sodium serves to bring the copper to the of a chloride, in which condition it can be readily ved out. The roasted ore is now thrown into which are furnished with layers of straw bundles le bottom, to serve as filters, and the water which

ET poured in, after passing through the mineral runs through apertures iu the bottom of the vats ioeivers, where it is allowed to settle. It is then a into a third set of vats, where it is treated with holding caustic lime in solution. This precipi- oxide of copper, which falls as a powder to the m of the vessels. This powder is collected, dried, msed in a low cupola furnace for a matt, which is lnently treated for coarse copper, and refined in the : manner.

A

THB UPTAtWFRfflr fTT t'WPWSH,

niEATMBNT OF THE BtTLPHIUES OF COFFER, 1

AT AGORDO, IN THE DBFARTMENT OP VBSl

The ore here obtained is a sulphide of minute particles of the suiphides of copper, sine, aud lead scattered through it, and remar] the small quantity of earthy impuiity which it It is esceediugly poor in copper, the average 15,000 tons of ore that are produced here being but per cent, of that metal.

The first process in the mctallurgic treatment' ore is the singular operation known as kern This is accomplished by piling 200 to 220 tons which is first reduced to pieces two or three diameter, upon a layer of wood, and covering with a stratum of ore that has been once roasted. pile being tindled, it is allowed to burn slowly, di a period of 8 or 10 months, when it grows cold, the lumps are found composed of two portions, outer or oxidised hull, that is broken off with hammers, and a firm kernel in the middle that contains the greater part of the copper as a sulphide. It would appear that the great heat given out by the combustion of the sulphurous exterior brought the interior of the mass to a semi-fiuid state, and that the copper in consequence of its natural affinity for sulphur, retained that element, and gradually concentrated itself at th centre, while the easily oxidised iron at the same time lost its sulphur and became aa infusible crust. The ore holding IJ- per cent, of copper is reduced by this process to kernels, forming 13 per cent, of the origiu&l me of the ore, and with. ao. axetaa richness

Till!: UJJTXiLUHGT OP coiteh.

ter cent, of copper. These kernels are now richer ore and fused for matt in narrow cea 26 feet high. This, after being roastedj I in a pecuhar leaning cupola furnace, Uccs a coarse copper that is nearly free froi jic and iron, and may he purified and refined .on the German hearth. oxidised portion formed in the firt roasting sd in vats, and subjected to the action of wat t dissolves out as a sulphate 65 per cent, of et it contains. The powder is then dried Kited to a second roasting by being used a ting for the large heaps while they are undergoinj >08tion. The powder is again treated with water, all but -i\i- of the original amount of copper tcted. The hquor holding sulphate of copper in on is now heated to about 122° Fahrenheit in tct with cast iron, and cement copper is obtained :i8 sent to the cupola furnace to be fused for mal )e process above described.

fCTlON OF POOE SULPHIDES AT VESLEDALEN,

te ore here ia an iron pyrites containing from 4- to &r cent, of the sulphide of copper disseminated ih it. It is abundant and easily mined. The n roasted in large heaps, and slowly, so that t lidea are decomposed and changed into soluU katea.

te result of this roasting is treated with water, i loluble sulphate of copper is taken up by the flui Q large vats to be precipitated.

flW

TOte WWititiCTWI "WWM"

A variation in the usual plan of throwing the eoppeij down from its solution by menns of the action of inn,! is here observed. That metal being too dear to b employed with profit, its place is supplied by phuretted hydrogen gaa. This is economically p by passing the product of the combustion of piuofl ID a retort, over a stratum of red-hot pyrites..'! precipitate which contains the copper in the-f( sulphide is however not very pure, and some J cultiea are experienced in accomplishing its econa reduction to soluble metal. I may here r sulphuretted hydrogen produced in the usual i with artificially prepared sulphide of iron aud snl acid, has been tried as a means of precipitation furnace at Freiberg, in Sasony, and not found a to the circumstances there.

Extkaction Of Copfeb From Thb Wateb ] Wicklow Mines.

The water from these mines holds in solutidj Bmall quantity of the sulphate of copper, a fact J appears to have been first observed a little i century ago. This water is led through a aeiii troughs inclined at an angle of 10° to 12°, andinra rupted at intervals by deep chests or hutches. Pieces of iron are ho placed that the water flows over theWi and the metal of the sulphate is thus precipitated u cement copper. Tliis is each morning swept from tha troughs into the chests, and at intervals is collected and sold. It yields 5U to 60 per cent, of pure copper, and costs but about 3/. per ton for attendance, aiEting,

THE METALLtmor OF COPPER.

JEECIPITATION OV COPPER AT SCHMOLLNITZ, IN j

Hungary.

L.t this locality pure water is led into old workings,

, allowed to circulate througli tlic waate heapa of

mt mines, where by the long action of air and

sture, sulphate of copper has been formed. This

iken up by the fluid, which is subsequently collected

, conducted into vats and allowed to remain in

tact with metallic iron. A cement copper is

ained, having in the most favourable cases 70 per

, of metal. Experiments here have sliowu that

cwt, of wrought iron, or 300 cwt. of cast iron, are

ired to throw down 100 cwt, of copper. By this

Bnious method 200 tons of cement copper

lected each year.

Reduction Of Coffer Oees At Att Swehen.

lie ores consist of a mixture of a small quantity ( sulphides of iron, copper, and zinc, with a large Ount of quartz with mica, feldspar, ganiet, and other Bates. After having been sorted by hand, they are ed together with coal and wood in the open air, I Toasted. 'Die product is sorted, the larger pieces Jken, and all that requires it is subjected to a second sting. The next operation consists in fusing the sted ore for the purpose of obtaining a matt. This accomplished in a cupola furnace, 18 feet liigh, and 3 inches across at the middle, into which threa allow air to he forced bj as ma-a crji

tozzles inches in diameter. In ranking ''Pl Anrge, it is sought to secure sucb a mixture, tliaH ibg produced will hold about 45 per ceut. of silica, lie matt S5 to 30 per cent, of copper. Such spearing beet adapted for freeing itself from if matt, and at the same time not being of sucb| nre as to attack the walk of the furnace.

The slag obtained in this fusion that liolds less of one per cent, of copper is cast awy ; the mBt£H Kkea to pieces about tlie size of the 6rat, and rojutH 1 heaps in the open air sL\ or seven times, unttkH Duch as possible of the sulphur and other ToMil mpuritics have been driven off. 'H

Fusion for coarse copper now follows in a rectangnlafl lupola furnacCj 18 feet high, and 3 feet across in laft. The bottom of the hearth is so deep that tbc I leavy, coarse copper may collect in large quanUtie) I md need only be drawn off at long intervali. I ifhe lighter slug which collects on the surface witli I a small quantity of matt resulting from the on- I reduced sulphates, are drawn off frequently and I laorted ; the rich sulphides are roasted again and ] itrought again to the fusion for coarse copper, while I 9ie slag holding considerable metal is sent back to tli8 I ixst fusion.

The coarse copper, which is unusually free from .adulterations, is purified on n, small German hearth, (figure 19), and since the principal impurity is iron, aiid this not being readily fusible, it is found necessary to add, iu the opei'ation, a small quantity of silicious slag jto combine with the ferruginous oxide as it is formed. "When the process of purifying is concluded, the metal f Jedeii from the hearth iuto wq tftovida, wad is ra()y

THE METAtHBEGT 0? COPfEB.

market. The method of smelting in use at tho tl known mines of Fahlan, in Sweden, where the t are very similar to thoee of Atvidaberg, fer sufficiently from that given above to require

rate description.

Thompson S Process Of Purifying Copper,

n

&.CCording to thia invcntoi', copper may be purified melting 100 parts of the metal along with 10 parts copper scales (black oxide), and 10 pHVts of ground fctle glass, or other similar flux. After the copper 1 been kept in fusion for half au hour, it will be md at the bottom of the crucible perfectly pure, jle the iron, lead, arsenic, &c., witli which it may een contaminated, will be oxidised by the scales 1 dissolved in the flux or volatilised. A pure copper I thus been obtained from brass, bell-metal, gun- ital, and several alloys containing from 4 up to 50 r cent, of iron, lead, antimony, bismuth, arsenic, &c. le scales of copper are cheap, being the product of Biy large manufactory where copper is worked.

Chapter Xiv.

The MBiiLLL-BDin Sepahitiun of Rutkb

It has been shown, in the foregoing pages, that by king advantage of the peculiarly strong affinity of per for sulphur; the slight disposition it possesses,

compared with other metals, to combiue with , :ygej]j and its high specific gravity, tUftt laoa

existing metallurgic processes for obtaining the j metal Lave been arrived at. There are a numbe plans in use for extracting silver from it or its 4 pounds, which rest on these and other impi physical and chemical peculiarities. A com discussion of this subject belongs to the treatise on tffi metallurgy of silver, and hence, only a brief outline the various plans will be found here.

, BT LIQCATIOlft

This is one of the most ancient methods of eitr silver from copper. It is founded upon the factl when copper containing silver is alloyed with t easily fusible metals, such as lead, and heated 1 certain degree above the melting point of the 1 metal, but below that of copper, the lead will I fluid and drain or sweat out of the alloy, carryi most of the- silver, and leaving an impure behind. In practice, 3 parts of coarse copper h(A silver are fused with 10 or 12 parts of lead, t equivalent portion of litharge rich in silver, operation is performed in a cupola furnace, am product run into moulds where it is rapidly i and removed iu the shape of disks, 3 to incl thickness.

These discs or cakes are carried to a li hearth, and being piled on their edges, are heatet means of burning charcoal to the proper temperature. The lead and silver flow from the copper compound, and are collected in a trough which is placed beneath for the purpose. The lead is then treated for tho tUver it contains, and flve co'pt laMs. M.\wlerg,o k

esome reSoing. Tbe plan, as ha> been bdbre ted, ia bg replaced at most ramacci hj more tte and direct metfaodi. Copper, faowcrer, u icated accorSing to tliis ftem in tite Hartz, lb is however assumed b; Karsten tbat as a Dpper tbat does not contain iiu>re than of one at, of silver will not paj tbe expense of liquatioa. aust depend, Lowever, greatlv upon tbe jaiccs of I , fuel lead, &c. In the Mnusfeld process, wc Ireadf seen tbat of one per cent, of alver was hind in the copper, after the liqoatiou w.is com- ; at AltcQiiii. the sUv-er left behind ited to jiy of one per cent, purification of the copper nliicb remains i rocees of liquation is variously accomplished. ' )f the most usual plaus is tu treat it in the fTiff furnace, ivliere the impure disks are exposed nurent of air, and without becoming melted, still of the argentiferous lead is sweated out and I d to run ofi' as an oxide. The lead that existed : disks at the beginning of this operation to tlm J Qt of 20 or 30 per cent., is thus reduced to about r cent., and the copper is now fused in the GL-rmauJ i to subject it to further purilicafiu.

i aftofH

lCtiok ov silver by tub ai

COAIlB£ COJ'PKR.

process is based upon the circumstance that the . vbich exists in coarse copper in a metallic statOi raised to a red heat, in connection withl D salt, is changed to a chloride ; and wlioitj

quicksilver in brought iato intimate contact witb t roasted mass, this ciiloridc is decomposed, and nmalgam with silver aud a small qnanlity of cog nnd iron is produced. The amalgam thus forn wlien removed to cast-iron retorts and heated, is composed, the quicksilver distils off, and' the si: remnining may be made by refining.

This sort of amalgamation is in use at Cziklowa Hungary, where coarse copper with of one per cen silrer is amalgamated to the amount of 100 tons yea

The cost of desilvering a ton of coarse copper her £5 15. T!ie loss of silver is about 7 per cent, of amount present.

The coarse copper is produced in the usual man roasting iu ijenps in the open air, and fusion in cupola faruaces. It is very impure, holding n arsenic and antimony, which prevent the adoptio either Xiervogcl's or Augnstin's method of extrad The coarse copper being raised to a bright red hes powdered beneath stamps and between revolving i stones. Tliia powder is roasted with salt and ' amalgamated in barrels in a manner similar to usual in the treatment of the ores of silver.

EXTItACTlOX OV SILVER BY THE AMALGAMATION COPPEIl MATT.

Tliis process which ia very similar to that ado in the usual amalgamation of silver ores, consist roasting the mixture of sulphides of copper, silver, i el cetera, that form the matt, as it falls from the fun witli a proper quantity of common salt and lime.

Tfae £rst furnishes cliloriue, hy mcana of wW

>us metals are turned into chlorides, wliile the lime composes the chlorides of iron and copper, but leaves e silver to be collected by the quicksilver in the sub- quent trcatmet. At one time this syBtem waa in A Rt Mansfeld, in Prussia, whei'C a matt containing Jrto 53 per cent, of copper and of one per cent, of her was used, but, at present, as has already been Knni, it is entirely replaced by the excellent method ' Zien'ogel. At Freiberg, ia Saxony, eKperiments ive been made to prove the practicability of the tethod, but the process invented by Augustia mnd more favourable.

l!llVOOL 3 METHOD 1 COFFER BT MEJ

EXTMACTING SILVER TTtOU a OF WARM WATER.

This process is accomplished by changing the sul- ! of silver into a sulphate by means of a careful laatiii, and subsequently dissolving out the sulphate jth warai water. It is sufficiently described in chap- lE XI. in connection with the Mausfeld method, of liidi it forms an important part.

at the f

AUOirSTDI S llETHOD OF EXTRACritrO SILYEK FI COFFER BY MEANS OF A SOLUTION OF SALT.

The circumstance long known to chemists, that 1 lioride of silver is somewhat soluble in a concentrated olution of common salt, was taken advantage of by .iigustin, of Eisleben, in an ingenious plan for sepa- ftting copper and silver. At Freiberg, in Saxony, this fYKsess is in successful operation, A matt is obtaiaej y repeated meltings, holding some 60 or 70 per crt f copper, and per cent, of silver. This ia powdfllf

lury liuclr, nod roasted in & furnace coustracted upi the same principle as shown in figure 17. Tin i-o!isted powder ia ground and subjected to a seconj roasting, and near the end of the process, about 5 cent, of salt ia added, which changes the silTeriatoi chloride. This roasted powder is now brought vessels similar to those represented by a, fig. IS, ftiii' treated with hot brine, which filtering through, cania with it the chloride of silver. Passing into precipitatiDB tuba, it is brought in contact with copper, which throw down the silver in the form of cement silver. Thiel collected, dried, and refined. The copper dissolved Hi the precipitation of the silver is carried forward to otha vessels and thrown down as cement copper with met&Uia iron. The lixiviated powder remaining in the vea is carried to a reverberatory furnace and smelted for coarse copper, which is refined in the German heartli. Tliis system, although more expensive than that last- mentioned, is much better adapted for minerals hold antimony or arsenic.

THE SEPAttATlON OV SILVER AND COFFEB BY DISSOLVIM THE COARSE C077EK IN SULPHURIC ACID.

At Eammelsberg, on the Hartz, a coarse copper, rjcli in arsenic, and holding of one per cent, of silver is separated from the silver, and the same time made valuable as an immediate source for copper vitriol. The copper is granulated and brought as a loose mass into tuba. Hot sulphuric acid ia then allowed to trickle over it, and the free access of air provided for. Under these circumstances, the copper slowly oxidises, and immediately becoming a 5tt\p\isAe, va ewcried ofif in fc

THE METALLUIlLiV Or COPPElt.

plution, which passiag through a series of trough:

tola, and deposits the salt lu rough crystals, the silver

the same time remainiug uncombiued ia the rat.

1 liquor is then forced back, heated, aud made to

1 over the copper and silver agaiu. The vitriol is

Uected, washed, dissolved io the hot mother liquor of

revious processes, and run off into vats to crystallise.

teen days after the solutiou has entered the vats,

8 considered to have crystallised sufficiently, and the

biother liquor is run out and forced into the vitriol pan,

. to be used to dissolve the rough salt. The re-

inder in the dissolving vessels holds about 2 per

mt. of silver, and is sent to the furnaces to be

melted. The works are situated near a sulphuric acid

lUufactory with which they arc in connection by a

Itllbe, and a yearly production has been reached of

B50O cwt, of viti-iol.

ABATION OF SlLVEll AND COFPLK BY DISSOLVI] IHE ROASTED MATT IN SULPHURIC ACID.

Freiberg, in Saxony, some experiments have

jcently been tried with good I'esult, in which the

silver-holding copper matt, that was formerly roa3tc<i

*ith common salt and treated according to Augustin's

Method, is osidised in the usual manner by roasting

I nd then brought into tubs, where it is subjected to t!ic

Ction of hot sulphuric acid. The copper is thus diaaolved

Out as a sulphate along with some iron, and the greater

part of the silver remains in the tubs undissolved. The

mpreous liquor is run into vats where it is allowed to

I and crystallise, and the vitriol formed ia sent to

tet where the copper that it cont-.vins poUr fov ftQWit

18 riiE aiETAij,uK5r~ 6J' (3lfPPESr

30s. per . more tlixn it would were it in a piw metallic form. The UDdissolved remainder, contdinuig'l aevernl per cent, of silver is smelted with lead, cupelled.

Chapter Xv.

Fbou time immemoria), copper has been used sirely for forming compounds with other metals. niicieuta, whose works of art still remain to us, appear to have wrought it chiefly in comhiuation ; and, at tW present day, the emploj' of the unmixed metitl less general than that of its alloys. It is not impHK bable thitt copper will unite with all the metallic ete- ments, but its alloys with zinc, tin, uickcl, and the precious metals ai'c the most valuable and the known,

This compound, which consists essentially of copper and zinc, is the most generally useful of all the uuroe- rons alloys at present known. It is first mentioned bf Aristotle, who states that the people who inhabited i couutry adjoining the Euxirie sea, prepared their copper of H beautiful white colour, by mi.xing and cemealinf it with an earth found there and not with tin, tia WM the custom in other lands. The Roman autbora of tll time of the early emperors, spenk of this earth, w\aA they knew as cadmia, of converting copper into chaleum, the ancient name for the ainc alloy. The

the cbaoge that tCK>k place, nud it is a remarkable

mple of the slowness by which man arrives at truth en led by experieuce alone ; that brass should have ide during a period of 2000 years, vvithout the (tal which brought about the change iii the copper J discovered. Agricola was the first to surmise that tB3 was a composition and not a transmuted metul, ffrass was made with the utmost secrecy iu Germany

ing several centurieSj and some faraihes were raised great opulence by its mauufactiire. The first brass rks erected in England, were put in operation in t9, at Esher, in Surrey, and the whole of the metal I then made of "rose" copper imported from Sweden; t parties interested in the exportation of calamine and pOrtation of foreign brass, succeeded in involving the in n disastrous law-suit which broke up the icern. Manufactories were however soon aftenyarda cted in Woolwich and Southwark, and iu 166S the mill for drawing brass wire was erected near chmoiid. At present, much brass is founded at iatol, Birmingham, Holywell, and various other parts the kingdom.

The properties which cause brass to be more exten- ely employed than copper are the following : — It is

. costly, being partly composed of a metiJ cheaper m copper, is harder, does not oxidise or rast so easily,

1 hence is more durable when exposed to atmospheric

ucies ; it melts at a lower temperature, and is hence tter adapted for small castings; it has not that idency to fill with minute bubbles, which property

so disadvantageous in copper founding; it cuts lOOther in the lathe, and will bear a higher polish ;

ooIouF may be made to resemble that of gold, wbicii

adapts it for purposes of ontament ; and lastly, it is more ductile and tenacious, and therefore may te fashioned by tlic hammer or drawn into wire more readily than either of its constituent metals.

The general designation, brass, embraces compound of copper and zinc in very different proportions, and tlie pliysical properties of the alloy vary largely as one or the other of the metals is in excess. The following table from Mallet, gives the proportions and peculiari- ties of a number of samples of brass.

P.

nccnurlu,

83 '8

11-*

Eeddisb yellow

Finely orvstalline

YeUowiflh red

Prinoea metal

79'G

20-*

Yellowish red

Rolled bras*

74 a

Pale yellow

Engliah brue

Oeraim brus

60 -S

Yellow

tOeiniBDlirucfoT ( waWlimnltei-i

fiS'S

Silver wLite

Conefioi.Ui

Generally, as the proportion of zinc rises, the hard- ness and fusibility of the compound increases, and at the same time the malleability and weight decrease. The brass founder in speaking of his mixtures, specifies llie amount of zinc only, it being understood that the ratio is to the pound of copper. The accompanying table gives some proportions made use of in practice,

'. iiEi'itt,l7fiaY or COPPER.

IS is made iu two ways: — First, liy melting er zinc and copper directly in crucibles. Secoud,,! ;tiiig copper with a powdered mixture of coal and j I calamiue, by which meana the cai'bon reduces] ic to a metallic form, and the two metals coming J tr are intimately blended.

first method was patented in 17S1, by James. I QD, and is now largely used for manufacturin

zinc is melted in a crucible and strips of copper , inged into it, until an alloy of somewhat difti- Bion is formed ; then the heat is raised, and tbol ing portion of the copper added. Such are this I affinities of the two metals, that the loss which be expected from the volatile nature of the zinc, 1 rented by its being retained by the more stable I . Brass of the first fusion is broken to pieces, 1 sited with a fresh quantity of zinc to obtain tlio d alloy. Each operation requires about eight or lours, and when coniplcte, tlie br.iss is niouldfd ates and treated lets and wire as (ed in the next

second method,

originated in times, is carried furnaces having kstiuction shown I accompanying The interior

L L consists of tick, and the furnace bottom B is formed of I nmay resting on an iron plate, both of which i

THE WETALLUHGY OP Ct*]'EI!.

are pierced by lidles timt serre to fiirnisli draught nud allow the Rshes and cinders to be drawn off. TheK furnaces will contftin eight or nine fire-ciay pols r t, wliicli, ill the aggregate, TriLl hold one, to one-and-a-half hundred weight of brass.

The calamine is jacpaFed bv breaking the natmd miueral into pieces about the size of a walnut. A charge, consisting of about five hundred weight rf these lumps, is plneed on the hearth of a reverbcratwy furnace, subjected to fire, nnd stirred with an iron till each piece becomes red hot throughout; this u sufficient to drive oft' the carbonic acid, and is tisiudlf effected in an hour. The loss by this process is 31to8S< per cent., and the mineral incurs a further loss of 8 4 per cent, by picking out worthless frngnsenta afisr calciuntion, the fire rendering the ferruginous deadf more apparent. Care and experience are nceeasartO perform the operation of roasting, for if it be aot complete, the zinc will not unite properly with copper, and if the ore is over calcined, the bna resulting from it will be brittle while if the heat made very intense, a partial vitrification of the silicioat matters will take place, and this portior canuot b# reduced again by the usual means. When the call- mine has been calcined, it is ground to a fine povdec, and tliis ia rendered more uniform by passing it ihrongk proper sieTes ; it then removed to a building oallfi the house, wbo'e it is washed in an appanta of pecuHwr construction, for the purpose of separatiiQ any extraneous matters that may still remain in it.

The zinc ore Laving been thus prepared, it is mind either with small pit coal or ground charcoal in tiM nroportion of rather more vVian. cne <a(

or coiTitii.

one bushel of calamine. The most carcfiil i

rs almost entirety discarded niinei'ul coal, dtm ley find that the sulpliide of iroiij with which it ia lerally coiitaniiiiated, either spoils the brass Of makes of an inferior quality.

Copper granulated in the asnal maimei* by lading it u the furnace into a vesset 6lled witli water, is then efnlly mixed with the calaraice and charcoal in the iportiou of three pounds of tlic copper to eigtit of I powder; with this the crucibles are laden and tliea ced, as shown iu the figure, within the furnace. The a are now surrounded and covered with fuel, the uace ia closed, and the fire lighted, iiml left nndis- bed for sis or seven hours. At the end of this 4od, the pota are at a white heat. The fire is now ivod by the addition of fresh fuel, hut as soon as acs of zinc oxide begin to appear, it is .igain slack- id that the operation may he lengthened, and the ) metals have ample time to unite. Three or four are required for this purpose, then the orifice in ; arch of the furuiice is opened, and with a large pair tongs, the various pots are draivu out, set in hot lea to retain their temperature, stirred well for a few inutes, and then all the melted metal is deposited in e. The scoria is now carefully skimmed oS', and the id remainder poured into moulds formed of two of granite laid half an iuch apart upon iron bars. r this means plates are formed that are usually (t long, 15 to IG inches wide, and half an inch thick, righing about 108 pounds. The entire operation ]uires from eight to twenty hours, depenJing on the of the material and the size of the furnaces. In older manufactories the time employed was mueli

greiiler, soiiictimes reacliing as much as four or five days. The moulds of granite, which were once im- ported at considerable expense from tlie Continent, are now ohtained from Cornwall, wliere an excellent mate- rial for their construction is found.

The cast plates are now transported to the rollil mill, where they are brought to the form of eheeti, which, by means of a pair of large shears, ai-e cut int? narrow strips. These are passed a number of timM through rollers till they an-ive at the condition of libauds, which are then cut into long slririffs, and passed to the wire-drawing department. The process of drawing wire from brass docs not differ essentially from that pursued in making the same commodity from iron : — A thin plate of hardened steel is pierced with numerous holes, gradually decreasing in size until as small aa the diameter proposed for the fiuest wire These holes must be made witli the utmost care, per- fectly round, and Iiiglily polished. The plate is then Bmeared with grease, to decrease friction; the COarsB wire is first drawn through tlie largest hole, then through the next smaller, and so on iu succession until the smallest desirable size is reached. The finest wire is often passed, in the last stages of its mniiu- faeture, through holes drilled in rubies. During the process of rolling and drawing, it is necessary to anneal the metal frequently, which is accomplished by raising it to a little below a red heat, and then suffering it to cool gradually, by which treatment it becomes soft and pliant. It ia not plunged into water, as is done with copper wire, though by so doing it would not bo hardened like iron and steel wire when thna IxeatM The largest consumption of Iwaaa

lure of pins, and here it performs an office that Mild be but poorly filled by copper. Brass foil is ide from a very thin sheet braaSj formed of 11 parts

copper to 2 of zinc. It ia beaten out under a jnmer worked by water-power, which gives 300 to lO strokes per minute, from 40 to 80 leaves being on each other. When brass is wanted for working to small castings, or foi- making other alloys, it is run ito Bmall ingots, about S inches long and it inches oad, in which form it is sold.

Bronze, like brass, is the generic name for a large 88 of alloys. Instead of ziuc, however, tin is here 3 secondary metal. The term is, moreover, made to ibrace compounds, not only of copper and tin, but

ao those containing lend and zinc in small quantities, third or fourth constitneuts. This alloy was one ol e earliest known, and in many connections it took B place of the dearer iron. Among the ancients it IS largely used for casting statues, and many articles domestic economy, and weapons, which have been 't us by the Grecians, llomans, Celts, and Peruvians, B composed of it. In the middle ages it grew to be iportant as a material for bells, and iu more modern nes it has been largely used for cannon; and although

; does not equal brass in the amount made and used,

ret the objects to which it can be applied are no less

.merous and important. Like brass, it is harder and

)re fusible than copper, and denser than the mean of

constituents. Its colour is usually reddish-yellow

when exposed to the air, a basic carbonate

lish-yellow ; I arbonate otJ

!RW Ttta HETJuxnun- 09 coppsb. ™'

eam>cT is formed which pwsesses the greenisb hi eommonlf seen on tlie Eurface of statues, and I which tbe alloy ia best known. Ttiia crust is ran admired, and tiencc often prodaced on new statu by moistening their surface with salts or acida. olutioa of pnrta of sal ammoniac, 1 part of oal acid, in 94 parts of distilled vinegar, ansven ll purpose very well.

Bronze possesses the singular property of beconui 80 malleable, that it may be hammered and coini Then it is heated and rapidly cooled, as by plunging into cold water ; and by heating it and allowing it cool slowly, it may be made to regain its former han ness and brittlenesa.

The following table will show the natnre of TOriw alloys of copper aud tin, and the uses to which tlti may be applied.

Yellowish rei

Mutol for nxU buxu Lnrge bella Su.a]]U;Us

The bronze of the ancients varied widely in its natu aa will be seen by the following analyses : —

Coppa.

m.

Laid.

,™.

Zino.

AluJlTMdS

Ss'O

U'O

I'Oo

Tooqaeni

lof Aleian-1 r the Great)

ScLmeid J

lO'O

MitflAerMch

11 ftom the)

S-5

Is-1

Flkillips

t Itam thBl

oa of Ha-!

So-r

0-T

PblUlpa

i iftiTiixtJftaf or Coppeb.

!t is remarkiible that iti the coins origin.itiug in ;ece, or iu uny of the Grecian colonies, zinc has not !n detected, while among the Roman coiua that tfti often occurs as a constituent. According to the experiments of Hoffmjin, it appem-a ,t for statuary bronze the e.ttfcme proportions that I be used with advantage are — -1st, the reddest and lest in copper, and hence the most expensive alloy y consist of S-1-42 per cent, of copper, 11-28 zinc, il 4-3 tin ; 2nd, the poorest in copper and cheapest Id yellow alloy, may be formed of 65'95 copper, 56 zinc, and S'-iS tin. The bronze statue of Louis I Fourteenth, cast in ll.i99, has 91*40 per cent. >per, 5-53 zinc, 1'70 tin, and 1-37 lead. The Leasing itue in Brunswick is composed of 89'IG copper, 0-49 10-24. tin, and O-IO lead. In the arts bronze is en used to form subatainces intended to withstand SBure and friction ; an excellent alloy for tbb pa te cDnsists of SO copper, 18 tin, 2 ziac. SteyheM

I recommended tlio fullowing composition for locumotite [ tutle boxes — 7 it copper 8 tin, 5 zinc, 8 lead; and a I compound used Scrniug in Belgium fur the same purpose cousists of 86 copper and 14 tin.

Cannon Metal. The proportions of the metals ' selected for this species of bronze are such as produce the toughest and most indestructible alloy. It ia among the richest in copper of all the bronzes, and consists generally of from 88 to 90 per cent, of tbat I metal, "ith 10 to I'Z per cent, of tin, the former metal furnishing the tenacity, the latter hardness. Thu greatest care is necessary to keep the compmmd clear of sulphur, lead, iron, and arsenic, for any of these would lesscti the value of the metal for the required purpose, lead producing a fusible mistare, and arsenic and sulphur causing brittleness.

The accompanying cut will give an idea of the adopted for casting cannon at Toulouse in Fraucc- The melting furnace, a, is of the reverberatory class ; a good fire built on the grate, g, melts the chai-ge tlit is placed on the hearth at A. Close to the furnace is a pit, M, in which the moulds, c c c, are built of the required shape, in an upright position, from a mixture of clay, horse- manure, and cow-haii-. Between the mouth of the fui-uacc and the moulds, canals are made for the passage of tJie fluid metal. The furnace is charged with old bronze and copper bars, and after these are brought to a fluid state, the necessary tin is added iu the form of small ingots ; the slag which forma on the surface is drawn off, the metal well stirred with poles of dry wood, that the mass may become homogeneoua. At the end of eight or nine hours, tlie chnre has become quite ftuid, auA. \i'y oijening tlie

fHB METJCttORGT OF corrEu.

t 1, the metal is permitted to flow luS After forty eight liouis* graduJ couling, he guns are ready to be remoied from the p t , tlie- )theu boredj turned, cnrefillj c\niiiined for flaws, mbjeeted to the ranoiis testa thought necessiry t

m the 1 L 11 h fit 11 b II l 1 11 1 r ught lUCQ The metal best adapted for large guns has leen shown by experience to consist of 11 parts of tin O 100 of copper, while that proper for small field- Bfes should consist of a mixture of 8 to 9 parts of ti

Metal. — This is a bronze containing a greate <et ceiitage of tin than guu metal ; the standard pro- lortiona are 78 parts of copper and 22 of tin; but zinc, ntimony, lead, nickel, and iron often occur in tha ,

irepared casting, aud are either iutroduced view of producing particular tones, or are impuritilfl conaetjueut upon the euaploynient of old brass or brenit 1

a their maaufacture. The iiccompnnying anidyui 1 sliow tbe composition of some aucieut and modem 1

BngliahbcU metal DannBladt ) chiineB, cftBt in [

1670 )

B11b of Bonen. )

So- Ts -9

21'6

m

O'O

0-0 1 Thmnpam H 2-1 Heyl 1

1-6 Qinrdin fl

;

The ase of a compound consisting of a number of metals is, however, not to be recommended since, as a rule, tbe pore hard alloj of tin aud coppei- gives the clearest soand, and the introduction of silver does not produce that beneficial effect which the fancy of poets ascribes to it. Bells of various tones are produced chiefly by varying the manner of casting, and the yw and proportions of the iuatrument. The apparatus used in their manufacture does not essentially differ rom that employed for easting cannon, though proTW sion need not be made for such a high heat, since tbe usual per centage of zinc makes bell metal comparatJTdjr fusible.

The composition of gonga or iom-toms, which are instruments formed like disks or shallow pans, and being beaten upon by a stick covered with leather, sometimes take the place ot \ieV\a, co-Rsvatsi. of ftboat W

THE MTTALIOtCT OF COWEfi.

Sll

copper nnd 22 of tin. The above-mentioned of bronac, wbich enables it to be made nible by rapid cooling is taken advantage of itt the rtruction of these instruments; the fused alloy is pt cast into a mould, after hardening', it is with' pwQ, and placed in a furnace where it is raised to a rry heat, then it is laid between two iron disks, iged into water, and allowed to cool; it is now umered to the desired form, and subsequently tem- ped by heating and slow cooling.

'his alloy contains still more tin than bell metal : tandard proportions are 66'6 per cent, of copper 33-4 per cent, of tin ; but these proportions are approximately adhered to. A small addition of tsenic ia often made, but too much will cause the to be easily attacked by the air : 33 parts of iqiperj 16 of zinc, and 2 of arsenic bare been used, and .mpmann found by the analyses of an excellent Chinese mirror, that it consisted of 80'S copper, 9'5 ted, and 8'5 antimony. The speculum of the great Hescope of Lord Hosse ia composed of copper with a tie less than one-half its weight of tin. Such loy is hard and brittle aod is capable of receivin|fj markably fine polish. Bronze/or Medals or Medallions. This alloy consists FOally of copper, with from 5 to 10 per cent, of tin, ftoagh a little lead and zinc do not injure the metal the purpose. The compound is melted, well mixed, Oored into moulJs, and when hardened quickly plunged ivater. It may now be brought under a presbj

where it will i-eceive a good impression, and aabse- iiuently by alow cooling it may be hardened. The medal thus formed may be given at once a delicate bronze colour by brualiing it over witb a soludon CQnsisting two of aa\ ammoniac, one part common salt, one of saltpetre one of ammonia, and M pnrta of strong vinegar. This when carefully applied, gives the beautiixil shade that is so admired, and which, by the application of the ax mixture may also be imparted to copies of works au or other subjects taken in pure copper.

Oebman Silver Or Argentam.

In China this componnd has been long known and esteiiBJvely used, and for many years it has been im- ported from that empire into Europe under the name packfong. In 177C it was recognised as an alloyof copper, zinc, and nickel, and since it was subsequenllv largely manufactured at Suhl, in Ilenueberg, in Ger- many, and from thence sent to England, it has received the name of German silver.

At present, very large quantities ai'e manufactured in England, and particularly at Sheffield, where it u formed into forks, spoons, vessels for the table, various other articles of domestic use, and being plated with silver by the electrotype process, is sold as R substitute for silver to all parts of the globe. When well made, it cannot be distinguished by an unpractised eye from many of the the silver alloys even when brought on the touchstone, but by dissolving a small piece in nitric acid, and adding a few drops of bydio- chloric acid, no milky precipitate la formed, w]

Id be the case, were a diver alloy treated iu the name way. Good German silTer is toagher aad harder than brass, and resists the action of the air much better ; it is susceptible of a very high pohsh, aud when

Ktperly prepared, may be rolled into plates, drawn aa

[te and wrought with the hammer.

The foUowiog analyses will serve to show the ele-

ental composition of several varieties.

1 Coppor.

Zioa.

Cbiwae piokfoag

Bngliaii Osnoui alnt

.! ai-3

.' 53 '0

ISl

40(3

lB-1

31ieffirid Gfrmsu ailiBr ..

n'O

The roiling of the materinls which constitute this Hoy, takes place in crucibles similar to those ii be manufacture of brass. TIte zinc is first melteij rith half the necessary copper, aud the compound i put into thin plates that may be readily broken. ' (Bother pot tbe nicVel is melted with the remainder ! copper, and after having been well stirred, tlie alloj copper and zinc ia added piece by piece, until the ' BOper proportions are arrived at, when the cooteoi* if the pot may be cast into ingots ready for use- mrity of the original metala is of the first mf aecuring a good German nlver a small sai' ,11 render it brittle and eailv a nickel, on account of jj, ' , ' lom free from that jj i

jprable difficulty to obHimpj..";

5H

THE nCTAlXITIUlt 6S* "COWEH.

iliscovery of n natural sulphide of nickel iu Sweden, I which is free from arsenic, has been very advuDtageous I to the manufacturers of German silver, by enHbling I them to supply in larger quantities & compound c resembling one of the noble metals.

ALLOYS OF COrPER WITH SILVER AND GOU

These two metals which are so largely making coins and jewellery, would be too soft am destroyed by friction were they employed in an entii pure condition. They arc, therefore, generally alloyed with some cheaper metal to give them the requisite durability. Copper will unite with either in any de- sired proportion, and without destroying their malle- ability. The small coins of Germany are often veiy rich in copper, so that after being a short time in use, they become quite red. The silver groschen, nude according to the Prussian law of 1821, have but 2 puts of silver to 7 of copper. Modern French silver coiiit have 9 part of silver to 1 of copper ; and tlioaa of England are aomewliat richer, having 37 parts of silver to 3 of copper.

The foregoing are the principal alloys of copper, there are a number of others, the names and propertiei of whicli are known to artisans ; among them are iombiK, consisting of S4'5 copper and 15-5 zinc; MankeimgvU, 70 copper and 30 zinc; pinchbeck, 88 copper and II zinc ; cymbal metal, SO copper and 20 tin ; Balh metal, SS parts of copper and 9 ziuc ; gilding bronze, 82-S cop|ier, 17-5 ziuc, 0-24 tin, and 0-02 lead ; white metal far . /onSj 32 parts brass, 4 part* imc, mi6. 1 af tin.-, ttUtiug,

copper 36-9 zinc 174 nickel; Chinese vkile r, 4fl'4i copper, STS cickel, 25'4 zinc, and 2'6

1 alloy of copper and arsenic, when consisting of SO ipec and 10 metallic arsenic, is white, slightly ductile, 1 more fusible than copper, and is not attacked by ! atmosphere. It is used for the scales of the ther- uneters and barometers, for dials, candlesticks, &c. is formed by smelting arsenic and copper clippings ether in an earthen crucible, under cover of a layer salt.

With iron, copper will combine in small proportions, B per cent., however, causes the iron to ireld badly, i a small quantity of the first-named metal combined Ui copper, injures its value for manufacturing pur- With aluminum, it forms an alloy of consider- malleahility and great hardness, and which is table of taking a very high polish.

Chapter Xvt.

""

! PROCESS OF MAKING ROSETTE COPPEll MALLEABLE.

The English system of smelting copper results in a jduct freed by the final " poling " of that portion of t suboxide which renders the metal brittle or "cold t " under the hammer. This however is not the s with copper purified on the German heMth and nerally brought to market as rosetle copper. The ; opraation here, aa has been sKo'svi (pW. AX]

loaves from 1 to 20 per cent, of the aub-oxide of copper dissolved ia tlie metal. This suhstaace must be removed before the copper caa be wrought, and the refining is often perfortaed by the manufacturer M artisan who purchases the metal, npou a small hearth, arranged like that shown in fig. 19. Instead hoireKC of the nozzle being inclined at a large angle so SB to throw the air directly upon the molten metal, it ia here ao nearly hoidzontal that the charcoal, which lies. upon the surface of the iluid, is only impinged upoiii The object of the operation, like that of " poling " ix- to bring about a reduction of the sub-oxide and pro- duce a copper without adulteration. The rosettes ara piled ia layers with good charcoal and fused, often with the use of highly heated air; the charcoal and oxygen furnish carbonic oxide which acts aa a reducing agent upon the sub-oxide, and changes it into metallic coppw. Assays are taken frequently and tried while cold snd hot beueath the hammer; when the metal hendi without cracking on the edges, the process is deemed complete, the charcoal is I'emoved, the contents of tlia heai-th allowed to cool slightly and then laded out of the hearth into iron moulds prepared for the purpose. This process which is usual in Germany, ia knowa M the Hammer gaarmachun [I .

Kollin'O Axd Uammerii<

The copper brick or ingot formed iu the refining process is often taken directly from the mould, and while yet hot carried to a rolling apparatus similar in its general arrangement to that commonly employed in working iron, Eigbt ov tew between the

THE WETALLlmaY OP COPPER.

la cylinders are sufficient to bring it to a long plate inch or less in tliickness. The heat gradually ireaaea until the plate becomes dark, it is theu lOved to a reverberatory furnace and placed upon a lea of iron bars which keep it auspended between hearth and the vault. Flames striking over the t-hridge paaa along the aurface of the plate and are tied off through flues leading downward. Thus heat ia raised gradually to a bright red, when the te ia again brought between the rollers. This ia itinued until a certain thinness ia reiiched, when two more platea are laid one upon the other and heated 1 rolled together.

the copper rolling mill at Rothenburg in Prussia,

tch ia understood to be the most extensive on the

itinent, the Irtrgeat plate that has been rolled was

'feet long, 9 feet broad, and half an inch thick. The

iper plates thus prepared may be plunged into water

remove the dark scalea, and aent to market, or may

further wrought into kettles, &c. Kettle bottoms

entire kettles ai-e hanimered from the flat plate.

r this purpoae tilt hammers moved by ateam or

ter power are employed, the atriking end of theae

lis is sometimes two or three feet long that it may

ich the interior surface of a deep vessel. One kettle

rarely beaten out at a time; ten or twelve platea are

lally fastened firmly to each other at the edgea, and

le entire mass hammered into ahape together. The

iges are tlica separated, the vessels taken apart and

Iven into the hands of workmen who beat the sides

bottoms smooth with small hammers. In the

Ication of very large copper bottoms for the boilers

sugar refineries a singular plan is adopted the hii%

n

itc of metat is cut iDto a circular form an a heavy Iiorizontal cixst iron ring that serves si by means of n rope running through a pulley 1 a beam above tlie plate, a ball of iron two O' hundred pouuds in weight is raised by men o: power 4- to 6 feet, aud allowed to fall successive! central parts of the malleable disk ivhich gr limes the form of a basin. A plate 8 feet in d

ly thus be henteu 2J feet deep in a day.

The process of drawing copper into wire is to that described in Chapter XV,, as nsual with

Soldering Copper.

Copper is soldered by making the surfiicei joined quite bright, free from oxide, and leT covering them with sal-ammoniac or rosin o before applying the hot soldering iron to fua together mth the alloy. The strong solder or the coppersmith consists of 8 parts of brass a zinc, a still stronger solder may be made of 3 copper, and 1 of zinc, and a softer consists of brass, I of tin, and 1 of zinc.

StTLPUATE OF COPPER OR

PITsIS

Among the commercial products formed from its compound with sulphuric acid, known ; vitriol, holds an important place. It is the su from which most of the chemical preparations metal are obtained ; it supplies in the art of d means of securing certain varieties of black, green, and blue ; it is sometimes adroinistert medicine; as a protection a£w.n irj ij

1 been occasionally employed to saturate timber, and e quantities are used in the art of electro-metallurgy. The separation of copper from other metals, by the i way, furnishes one of the most important sources the salt; but when it is made the object of special Dufacture from the metal upon a large scale the owing plan is adopted :— A reverberatory furnace usual construction is charged with old copper plates, 1 brought to a white lieat. Sulphur ia now thrown md the draught closed until a sub-sulphide has been duced, the draught is then opened and air coming in tact with the hot sulphide, a sulphate is formed, ether with an iuaoluble oxide. The roasted mass ihen treated with hot water until all the sulphate been carried away, and the insoluble remainder is ill lieated with sulphur in the furnace, and lixiviatedj I this process repeated until the whole of the copper hanged to a sulphate. The solution is ran into vats tl allowed to deposit crystals which are drained and t to market.

Ajiother plan for obtaining this commodity is largely use. The scales which fait in hammering and rolling (per, are carefully collected and mixed with sti'ong phuiic acid in wooden vessels lined with lead. The ture is warmed and agitated by steam being blown 3 it through a tube opening near the bottom of the "When the acid has become saturated with oxide copper, it is drawn off into other leaden vessels and (wed to crystallise.

Blue vitriol often comes into the trade largely iterated with iron vitnol of copperas. This ity, however, may be detected by the greenish ir, when much iron is present.

TmE aTETAr-rrRGt tw cowes?

When asolution of the nitrate of copper has it Copper precipitated aa an oxide by adding lime in piire state, and the cupreous product is triturated nifli lime after it is nearly dry, the result is a substance d a fine velvety lustre, known as blue verdiler, cendres bleuts en pdie, of the French, is a compoaiti resembling this in many respects. It is made by trab- ing a solution of the chloride of copper with liydnbl of lime. The precipitate thus obtained is mixed witli solution of pearlash and ground in a colour mill. ] ia sold as a paste for painting, or printing paper ingB, or when di-ied and worked into the proper form " is used by artists for crayons.

SCHWEfNFURTH GREEN.

This henutiful colour was discovered in 1814, in, Schweinfurth, and the method of its preparation H secret until 1822, when the resuarchea of Liebig indi- cated its nature, and opened its manufacture to ths world. Its preparation is easy ; — 50 lbs. of sulphate o( copper, and 10 lbs. of lime are dissolved in 20 gtdloni of good vinegar, aiid a boiling hot solution of white arsenic quickly added. The misture is stirred sevenl times and then allowed to subside. The pigment ii cooled on a filter, dried, powdered, sifted, and afiei rubbing with a little muriatic acid is ready for usi

THE ACETATE OF COPPER Oa VERDIQBIS.

This salt is employed in painting and in calico print- ing. When puie, it haa a feae \3VuiiaV-%tfte. <

THE METAIXURGT of copper.

kible in ammooia, and contains 43 per cent, of the ide of copper. The best verdigris is manufactured IVance, at Grenoble and Montpellier, by packing i of copper in casks with alternate layers of nenting skins and pulp of grapes, which form the lee of the wine presses after nearly all the juice I "been extracted. From 15 to 20 days are required sorrode the plates sufficiently. They are then taken n the casks, leaned against each other, and fre- mtly moistened with water during several weeks. i verdigris, which then is found in a scale covering Burface, is scraped off and the copper plates suh- led to a fresh treatment, until they are entirely con. ted into verdigris. The salt is now kneaded into a te, packed in leathern bags, di'ied, and sold. The digris made in nortliern Europe and in England, is llally manufactured by employing cloths steeped in roligneous acid, instead of the refuse of the wine- press, and ia not equal to that naade by the former method. Chalk ia sometimes used to adulterate ver- digris, but may readily be detected by dissolving the icted substance in hydrochloric acid, in which case e presence of the lime, bubbles wiU appear.

METALLrRGY.

iln the early stages of the beautiful and valuable

I depositing metals from their solution by galvanic

[ency, the metal which is the subject of this treatise

B the only substance sought to be precipitated. In

ir 1837, while observing the action of a constant

' formed with a solution of the sulphate

.Mr. Spencer noticed that the plate usei

inic I

ate of j sd forH

Jibe negative pole became coated with i I with the exceptibu of tfaoae spots upon wfa I been accidiititally dropped. This ciicums I attcntioii to the subject, and subsequent ex I of whom Walker, Jlikiugton, Smee, aaft I been eminently successful, gradually dei r to its present condition.

When copper ia deposited, the sidphate t

ia the salt, the solution of which is unifonnl

The required solution is formed from the b]

commerce by dissolving that substance in

until no more will be taken up, then all

f stand until it is quite clear, and adding one-

' watcTj since a saturated solution is not de

fluid is then pot

Fia.s. vessel, n, fig, 22

I . copper plate, c, is

the edge, so as U

IB to be copied or ph

HB Jl medal ni — is attach

and hung also in 1

M " Opposite and paral

plate. An electr

which may be ge

L any species of batte

I is passed through

-to the copper plate. The vitriol, in solut

decomposed, the electro -positive element or

gobg to the negative pole or the medal m, e

a imiibrm and solid coaling wniv i.,

tic acid thus set free, attacks tlie coj)]";!' jitjitu v, renews iu the solution the sulpliate wliJcli is de-

.posed by tlie current. This action may he continued until ii thick coatiu{j ma on the surface of the medal, the deposition of ich will be slow or rapid according to the strength

the curreut of electricity. Any other object having conducting surface, placed at m, will likewise he

,ted with the metal in soiution, and thus a cheap a.teri!il may be so plated that it will resemble the ore valuable metal thrown down upon it. Ifj however, the surface of M is not a couductor, no etal ia deposited, hence, in the foregoing instance, in der to prevent the medal from being encased in a ale of copper, which could not be readily removed, its xik part and edge arc covered with wax, and only its se left exposed, and this smface, that the cast may it adhere to it, is moistened with a little sweet oil and ;bbed with silk till it appears dry. To -coat objects which are nou-conductors, a fine wider of graphite or blacklead may be laid thinly er the surface and introduced into the irregularities ith a brush ; the object may now be treated as in the

IB of the medal, and thus, by etching, so as to form

rough exterior, glass or porcelain may be given a Brmanent coating of pure copper. The above- iscribed process, it is evident, will only give a reversed tpression of tlie medal. In many cases it ia desirable

have an exact copy of the object; here, an exact iprcssiou of the surface to be copied, is taken in , isible metal, was, a composition of glue, plaster ( aris, or gutta pereha, and the metal thrown do* ion this as a mould.

Not onlr is it possible by tbe processes of eleetto- tnetnllurgy to form facsimiles of various objects Id copper, but the same luay be formed in Tarious allci}>% by tbroiriug down together, from a mixed solution, the metnls of which the alloy may be composed,

VTheti brass is to \ie deposited by this method, Rolalion is placed in the vessel Bj having the following composition —

1 port of Ealphate of copptr in t parts of hot water. 8 faiie ormlphBte of ting in 16 purta of bot water. 18 itU of rjanide of polasdoiB in 36 ferte o!bai water.

These are raised, 250 parts of water added, and the objects to be copied introduced as above- dcEcribed.. Instead of a copper plate at c, one of brass is used, tlie solution is kept during the operation at a heat approaching boiling, and a powerful battery employed.

The applications of the principle of eleetro-decompi>' ntion iu the arts are very numerous. In the working of copper, the most important are those wliicli are con- nected with printing and engraving, A hard copper plating is thrown down on the face of common type, thus greatly increasing their durability, and entire ste- reotype plates are made by taking the cast of the type in gutta percha or plaster of Paris, and depositing a thick plate of copper upon this reverse mould. Solid copper plittes for the purpose of the engraver, which on account of the difficulty of casting copper without bubbles, are often imperfect when made by the dry way, are formed with certainty by depositing the metal from its solution. A more beautiful employment (rf the art is found in reproducing elaborately engraved

fttes, Ustinllf, copper plates after passing thi

press 600 to 1000 times, become ro worn as to distinct impressions; by electro-mctallurg;y, however, plates may be multiplied indefinitely, and the arpoess of the originals retained. Through the idaess of Col. James, I had recently the pleasure of ipecting the admirable electrotype department of s Ordnance Suney at Southampton. The plates, graved by the usual processes, are duplicated by strong battery, essentially by the plan above icribed. Thus, perfect fac-similes of the most elabo- e works are obtained in a few weeks and at a com- batively small cost, and the clear engravings of the vey maps are by this means produced at a much rer cost than could otherwise be done. To the lover of natural history the electrotype offers 'o processes of esceeding beauty and value. By a mple adaptation of the principles above detailed, the ist accurate copies may he made of any vegetable or imal substance that will remain undecomposed in lution for a few hours. Thus the most delicate hairs id tendrils of plants, and the smallest insects may be lated with metal, and preserved. The second process. Inch is known as "Nature-Printing," is generally led for obtaining impressions of plants, and is often Huccessful that impractised eyes mistiike a simple cture made by this method for an escellently dried tecimen. It has been used in the preparation of that egant work "The Ferns of Great Britain and Ire- id." Tiie plant to be copied is pressed with great rce upon a plate of lead, and thus made to leave a elicate nnd perfect impression of itacif upon the soft i etal. Then by means of electrical action, these plat

of load have copjicr deposited upou them until a al is formed heavy euough to print from.

This is then supplied with the various upproprintl colours, and imprcssious are taken as iu ordinary' copjier plate printing, the inked plate, with the liheet of J paper laid on it, being passed through a pair of rallen, ( one of whieh is covered with four or five thickuesaea of . blanket, which, pressing the damp paper into all the I indentations upon the plate, causes the peculiar raised / or embossed appearance of the impression.

The scientific world is deeply indebted to the eini- I neut savan, Piofessor Haidinger, of Vienna, who, ia I 1850, made the suggcstiou which led to this appUcation I of electro-metalliugv,

Chapteu Xvii.

TsH Staiiskcs .

The following table* gives, as nearly aa can be ascertained, the amount and relative proportion of copper produced by the various countries of the globe. It will be observed that within 25 years the number of tons sent to market more thau doubled, an increasa which ia chiefly due to the discovery of new cupriferous regions in Chili, Cuba, Australia, and the United States. Yet during the same period the price of the metal has risen very notably.

WMtnoy's "Melallic WealUi of the Uaiieil Statea."

The Metallurgy Op Copper.

fO

o

Co

Co

Co

Co

r-l

Co

Co

lO

r-l

r-i

r-i

Us

o

o

Co

(N

Co

(l4

Co

rH

O

o

o

o

o

O

O

O

o

o

o

o

o

o

o

o

o

o

lO

o

o

o

o

o

o

o

o

o

o

ao

o

kO

Co

o

Co

Co

o

o

Co

o

O

H

o

T-\

Co

rH

Co

T-i

rH

Go

b-

op

Co

o

Oo

Oo

r-i

r

Co

o

tH

Co

to

rH

r-i

rH

Co

Co

r-i

rH

J

to

Oo

O

o

O

o

o

O

o

O

o

o

o

o

o

O

o

o

O

o

o

o

o

o

o

o

o

o

o

to

o

o

"Th

Co

o

o

Co

o

kO

Co

o

H

Co

T-i

Co

rH

r-i

Co

C5|

r-i

Co

§

t>.

l-t

Ud

tN.

(N

r-i

o

o

5?

m

T-\

Co

r-l

Co

Co

r-i

Co

C<l

rH

r-i

Co

o

£

Oo

rH

O

o

§

o

o

O

o

o

o

o

O

o

o

o

o

o

la

O

o

o

o

o

o

o

o

o

kO

O

Co

1:

o

r-<

U3

o

T-t

iO

T-i

o

o

H

Co

r-i

T-\

cq

i-H

Ol

r-<

Co

O

o

o

o

r-i

Oi

rH

O

P4

Co Oo

r-t

O

o

O

o

o

O

o

o

o

o

o

o

o

o

o

to

O

o

o

o

o

Oo

(N

rH

kO

Wi

kO

kO

o

H

Co

rH

Co

r-i

The production of the globe is at present about

68,500 tonSj Great Britain standing first upon tlie list ibllowcd closely by Chili and the United States.

The records of the Cornish "ticketings" form aii interesting series in which to trace the history of the axigress of the copper trade by England. They extend more than a centnry with considerable complete- taa, and indicate in a (striking manner the pre-eminence id importance of the Cornish mines as a source of luttional wealth. The gradual decline in the per- centage of the ores sent to market, has been justly ascribed by Sir Charles Lemou, to the improvements which have taken place in metallurgic processes which have made the profitable employment of poorer ores Sssible, Further, the importance of rich foreign ores iBnd regulus, has necessitated (see Chapter X.) the use ;of minerals holding a lower percentage of metal, in lirder to produce the proper working mixture.

Showing the amount and value of copper ores soW Cornwall from 1726 to 1775, inclusive.

priM

(BUlmL

s

172810 1785 ,.. i7afitol745 ...

et,aoo

76,620

473,600 660,108

6,4G0 7,662

47,350

68,010

17wir6B ... 17BBtol7BB ...

Bs,7B0 169,699

731,457 l,aJ3,045

e.879 16,070

73,045 124,304

178810 1776 ...

261,273

a 14

1,778,337

26,427

177,838

The Metallurgy Of Copper.

Table Iii.

Showing the quantity of copper ore, in tons of 21 cwt., sold at the Cornish " ticketings with its money value, the amount of fine copper it contained, and the standard and percentage from 1771 to 1859.

Tons of Ore sold.

Fine

Copper in

Ore.

Honey value.

Standard.

Per

cent, yield.

£,

&

27,8S6

189,609

27,965

189,605

27,663

148,431

80,254

162,000

29,966

192,000

29,433

191,690

0>j

28,216

177,000

24,706

140,536

31,115

180,906

24,433

171,231

28,749

178,789

28,122

152,434

35,799

219,937

36,601

209,132

36,959

205,461

39,895

237,237

oJ

38,047

190,738

31,541

160,303

33,281

184,382

42,816

320,875

43,689

336,189

43,313

866,564

47,909

377,838

Wi

'TBS MBfATiMi'lliyV Ctfi'py'iC

Iraarf

Finn

MMiey volne.

Per

Oniidld.

BlfllliloPd,

wnl.

yield-

£

1Tb3

51,358

422,633

Ci, 273

*B23

469,664

12i"'

65,981

350,925

ISOl

Ea,811

£267

476,313

1S02

446,094

no 13

60,fi68

S'S

64,B37

570,SiO

78,452

862,410

I80S

730,845

183 5'

71,894

609,002

]80S

67,867

495,303

1S09

70,245

770,028

66,048

669,913

66,490

563,742

TE,6ie

608,065

113 oJ

686,673

87,482

7B36

766,82*

79,034

583,103

83,053

70Je

541,737

109 of

Jl'E

IBir

75,816

422,426

80,525

687,977

121 of

728,032

92,672

98,80S

628,832

8'I

106,723

676,285

97,470

618,933

102,200

80S2

003,871

no 0-

182S

110,000

743,253

118,708

798,790

123,4Sg

10,450

765,353

130,866

S961

759,176

125,902

525,834

135,665

10,360

784,000

IBSl

12,218

817,740

139,057

12,099

835,813

138,300

11,185

358,703

no Of

Tut

METAXLtmGT OF COPrEB.

OraaolJ.

sr

atmdcnl.

Per

N0.D(

£

£

14S,2Be

11,224

387,902

oS

163,807

32,271

896,401

ias6

11,839

957,752

Ingi.

140,753

10,823

908,613

1S38

146,ess

11,627

857,779

109 3 J

lase

16B,Efil

19,460

932,207

18*0

i4T,2ea

11,037

792,768

7'5

136,090

819,947

7'4

18*2

135,681

322,370

144,800

10,926

804,445

7'5

162,687

11,246

816,246

157,000

12,239

836,363

166,013

12,447

386,785

7'8

143,074

11,966

830,739

166,816

12,809

826,030

So

I44,S3S

716,917

18E0

160,890

11,824

814,037

164,2B9

12,199

808,244

7!i

152,802

11,706

828,067

S2

Iss3

130,096

n,8S9

1.124,681

B'-l

1S64

180,687

11,779

1,163,766

6'fi

B6

18Cs

138,9G9

12,241

1,212,686

6-S

18Ge

203,177

13,633

1,241,836

6'S

18B7

191,798

12,177

1,201,270

6-fl

182,391

11,831

1,057,634

183,944

11,838

1,079,075

6'4

The

United

Kingdom produced in 186S, from tb

B

aper min

3S that are reported, 226,852 tons of ore,

Talued

at £1,3;;

6,535, which contained 14,456 tona of

fine CO

iper, val

led at £1,802,693. The total quantity

of cop

er produ

ced from British, foreign, and Colonial

ores (1

iring th

same year, was 31,011 tona, valued at

£3,417

HETALLCEGr OF t

The imports of copper dui'iiig tlie yetir 185S were, ecordiug to Parliamentary returns, as follows : —

In the year 1858 tlie various smelting companies rcliased ores and regulus as follows : —

SB Bojftl Conpuijr ..

AD and Co

! Qranfell and Som Willyama, and Co. imi, FoBler, nnd Co. SI, 1 and BIkiogtou ... 2J

lick Lajdtart 12

Miaere' UoiDpivn; 15 SB Lambelt 9

Sevtoa, Keate, and Co. Alkali Company Briton Ferry Copper

Sritisb and Foreign Cop-

Focliet Kook Smelt Com-

pauy

Mona Mining Cpmpanj...

Copper ore

Uovrought in Old DOppur

78,841 I Copper part wrougUt i

ia,45n biira

rieka,taj. 8,S1S I Platea and Coin

S52 I Copper maaufactnTes ,.

1.0G9

doming principally from Chili, Cubi, Spain, Australia,

md tlie United States,

The total iimouut of metallic copper exported during lie same period ivas 24,788 tons, 5819 tons of which went to tbc Britisli East Indies as sheets, nail, and yellow metal, and 'li56 tons to France and Belgium in tlie form of unwrought bricks and pigs.

According to the circular of Messrs. Dupee, BecV, md Snyls, the produce of the Lake Superior region in .859, amounted to 4,300 tons of ingot copper, valued t about £400,000.

THE ?i)BW YORK PUBLIC LIBRj

RBFEHHNCE DEPARTMENT taken from tfae BuildinS

Q1 1-

Hv,

f t: