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furnace, which before the fufion had been flop-ped up with a {hovel full of wet clay mixedwith about a fourth of new coal, which preventsthe clay from hardening too much, fo that thehole may readily be opened by an iron pick.

The rough copper as it runs from the furnaceis conveyed by a gutter into a large kind of bucketfufpended by chains in a well through which a{bream of water is paffing, and here, in fallinginto the water, the metal is granulated, whichtakes place without explofion or danger, and itis then drawn out by railing the bucket.

The copper is {till however extremely impure,though apparently in the metallic Hate, beinggrey and perfectly brittle, and {till mixed witharfenic and fulphur, to feparate which is thework of feveral fubfequent precedes. It is thenremelted and granulated twice more or oftener,each time throwing up a flag in the furnace,which is removed before the plug-hole is tap-ped ; but as this flag contains fome copper, itis not call into moulds as the firfl, but workedover and over again with the frefh charges ofcalcined ore. The number of fufions and gra-nulations is entirely determined by the natureof the ore. The granulated mafs is then meltedand cafl into pigs, which have a bliflered ap-pearance on the lurface, and are broken up androafted for one or two days in a low red heat,and again melted and roafted as before forfeveral times till the metal is confiderably purer,and at laft is cafl in oblong iron moulds about14 inches in length, when it is removed to theRefining Furnace. Here it is again melted withthe addition of a little charcoal, till it is broughtto a fufficient purity to bear the hammer, and iscow good faleable copper.

It is obfervable that in the former procefswhen the crude and brittle metal is cafl in fandin the form of large pigs or ingots, the bellpart of the copper rifes to the furface, and whencold may be knocked off with a hammer, form-ing a brittle cruft about three-quarters of aninch thick, of a grey colour and a fleel-likefradlure.

Thus by a feries of fucceffive calcinations andfufions in the fimpleft manner poflible, the com-mon copper ores are freed from arfenic, fulphurand earthy matters, and gradually brought tothe flate of malleable copper. Where a varietyof ores from different places and of differentfpecies are brought to the fame fmelting-houfe(which is the cafe in many of the houfes atSwanfea and different parts of the Briflol coaft)much technical judgment is exercifed in forting

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the ores and diftributing the charges for thefurnace in fuch a manner that the more fufiblewill affift the reduction of the refractory, andthe poorer will be made more worth workingby the addition of a portion of the richer ores,and the like.

The fubfequent operations whereby the ingotsor pigs of malleable copper are formed into fheetcopper, wire, nails, bolts, cauldrons, and aninfinite variety of manufactured articles, do notcome within the province of pure chemiftry : itmay be fufficient to obferve that the hammeringrenders the metal much more uniform, clofe,and duCtile, but this requires to be frequentlyalternated with annealing at a full red heat, toprevent the metal from cracking under thepowerful preffure to which it is expofed. Im-mediately after the laft annealing, the copperplates are quenched in urine, which fomewhathardens the furface, and gives it that rednefswhich is confidered by the merchant as onemark of the purity of the metal.

In the reduClion of the copper ores of Neufolin Hungary , lead is ufed in the refining part ofthe procefs b in the following manner: therough copper is fpread on the bed of a furnace,and when it has been fix hours in fufion, fomelead, in the proportion of from 6 to 8 per cent,of the copper, is thrown in, which immediatelybegins to vitrify and to form a thick fcoria along ^with the impurities of the copper, which isfeummed off fucceffively till the whole is ex-haufted and the copper remains fine and clear.This procefs lafts from 10 to 12 hours, with 50quintals of raw copper. The fcorite retain aportion of copper, which makes it anfwer towork them again.

The power which the vitrified oxyd of leadhas to fcorify all metals, except gold, filver andplatina, is amply fhewn in the procefs of AJfay-ing, and hence it mull happen that in refining,fome of the copper becomes oxidated togetherwith the lead ; but the fame procefs of allaying{hews that copper requires a large portion oflead for this purpole, and therefore the lattermetal in fo fmall a proportion as 6 to 8 percent, is probably a moft ufeful addition wherenot too expenfive. For of all the common im-perfect metals, copper is that which fcorifiesand oxidates with moft difficulty when in fufion,and therefore the fame method, with fome littlevariety, may be pradifed to feparate lead andtin (for example) from copper, as any or all ofthefe metals from filver or gold, care beingtaken in the former cafe not to carry the fcori-Vletali. tom- 3.