Metals. MINER 
colour and luftre of lead, and of a flat texture. Found in 
the .mines of Hercynia; and contains i'ulphur, copper, 
filver, iron, arfenic, and lead. 
25. Cuprum Hercynicum, or Hercynian copper: hard- 
ifli, with a dull luftre and dark-grey colour. Found in 
the mines of the Hartz-foreft ; and contains a confider- 
able portion of copper, forne antimony and fulphur, a 
little iron, and a very fmall quantity of filver. 
26. Cuprum Dalicum, or Swedifti copper: with metallic 
luftre, of a fteel-grey colour, and red ftreak. Found in 
the mines of Dalicum in Sweden, and Freyburg in Saxony. 
27. Cuprum fulvum, copper pyrites, yellow fulphuvet 
of copper, or mundie : yellow, with metallic fplendour, 
emitting fulphurous flames and vapours when thrown on 
hot coals. This is the molt common ore in the mines of 
Cornwall, Ireland, Siberia, Hungary, Sweden, &c. and it 
occurs in innumerable varieties and proportions, maflive, 
diffeminated, or cryftallized. Colour light yellow or 
greenilh-yellow, fometimes verging on the fteel-grey; 
when tarnilhed by the air often variegated with gold-yel¬ 
low, blue, green, or red. Texture even, or imperfectly 
conchoidal, rather foft. It deflagrates with nitre, does 
not efflorefce by expofure to the air, nor effervefce with 
nitrous acid ; before the blowpipe it decrepitates, gives a 
o-reenifh fulphurous linoke, and melts into a black globule 
which gradually takes the colour of copper: it is com- 
pofed of copper and fulphur with a little iron : it tinges 
borax green. It is not in the fiighteft degree malleable, 
but yields eafily to the file ; rarely ftrikes fire with fteel. 
Copper pyrites often undergoes a fuperficial alteration 
of colour, in confequence of expofure to air ; palling 
through numerous iridefcent ftiades, principally of pur¬ 
ple, blue, and red ; thefe afterwards tarnifh and become 
fainter ; and at laft are blended together into a uniform 
dull brown or greenifli brown colour. It fometimes oc¬ 
curs in a mammillated form ; the furface of the tubercles 
is either very obfcurely iridefcent, or of a light greenifli 
bronze colour ; and here and there incruftated with fmall 
irregular cryftals of the fame nature, but of a bluilh-black 
colour, dilpoled in the manner of fillagree-work. The 
dark colour both of the mammillated mafles and of the 
cryftals is only fuperficial: the interior fubftance is of a 
uniform yellow. 
Copper pyrites is the ore from which a great proportion 
of the copper of commerce is obtained. The firll part of 
the procefs confifts in the feparatioft of the fulphur by 
means of fire, and is technically called roafting the ore. 
This is conduced either in the open air, or in large 
chambers ; combuftible materials are mixed with the ore 
that has been broken down into fragments of a conve¬ 
nient fize ; and the whole is then piled in heaps and fet 
on fire. In all inftances it is neceffary that this procefs 
fliould be repeated three or four times, in confequence of 
the ftrong degree of attraftion that exifts between the ful¬ 
phur and the metal : in fome ten or twelve times, 01- 
even more. The roafted ore is afterwards melted in a 
furnace 5 from which itpaffes into batons placed beneath : 
in this ftate it is of a blackifti-brown colour, and very 
brittle ; containing a lefs proportion of fulphur than the 
native ore, but in other relpecls equally unfit for econo¬ 
mical purpofes. It is therefore broken up, and again and 
again fufed ; the procefs being frequently repeated as 
many as fix, or eight, or even ten, times. When by thefe 
repeated fufions the fulphur has been nearly feparated, 
the copper lliows itfelf in diftinft patches diffuied through 
the fubftance of the imperi'eftly-reduced mafs ; fometimes 
accumulated in very delicate capillary filaments. 
But, after all the fulphur has been feparated, the cop¬ 
per generally contains fome portion of iron, or zink, or 
other metals 5 and thefe are feparated by a procefs ibme- 
what analogous to the cuppellation of gold ; for the cop¬ 
per is expoied while in fufion to a conftant current of air, 
which oxydates the other metals. The metallic particles 
th us oxydated are collected upon the furface of the melted 
copper, in the form of drofs 5 which is removed from time. 
Vol. XV. Mo. 1060, 
A L O G Y. Metals. 493 
to time, in order to expofe.a frefh furface of the liquid 
metal to the aftion of the current of air. Indeed the com¬ 
plete reduction of the copper is altogether a very tedious 
procefs j and, from the obftinacy with which the fulphur 
adheres to the metal, it is often a very difficult procefs 
alfo ; and, this will account for the difference obfervable 
in the copper of commerce ; which in fome inftances pol- 
felfes the metallic character in a much higher degree thari 
in others. Thus it is found that the copper employed in 
flieathing Ihips fometimes lafts a much longer time than 
it does at others. The defeft may often be owing to want 
of attention during the reduction : in fome cafes it may 
depend upon the nature of the ore. 
When this ore contains a very fmall proportion of me¬ 
tal, it is often employed for extrafting the fulphur prin¬ 
cipally ; which is done by roafting it in chambers commu¬ 
nicating with flues, in which the I'ulphur feparated by the 
heat is collefted. The roafted ore is afterwards wafhed 
for the purpofe of extrafting the fulphat of copper that 
has been formed during the procefs •, the water holding 
this fait in folution is collefted ; pieces of iron are thrown 
into it, on which the copper is precipitated in a metallic 
form, which being coliefted is called cement-copper , or 
copper of cementation. See farther under the word An- 
GL.ESEA, VoL i. p. 70a. 
28. Cuprum eampanarum, or bell-metal ore : hardifh, 
ponderous, with metallic luftre, of a bluifh fteel colour. 
Found in Chili, and in Cornwall near Wheal-rock ; and 
confifts of copper and tin pyrites, with fometimes a little 
arfenic. 
29. Cuprum aurichalceum, or brafs copper-ore : of the 
colour and luftre of brafs ; malleable. Found near the 
river Laxa in Chili; and confifts of copper-pyrites, and 
blend, or fulphurat of zink. 
30. Cuprum Cornubicum, or Cornifh copper-ore: grey j 
mixed with fulphur, zink, tin, and arlenic. Found in 
Cornwall; and is probably only a variety of the bell - 
metal ore. 
31. Cuprum vitratum, grey fuiphuret of copper, or vi¬ 
treous copper-ore: foft, with metallic luftre, of a lead- 
colour, eafily melting before the blowpipe. The origin 
of the term vitreous leems to have arifen in this inftance 
from a fimiiar miftake with that defcribed under the head 
of fuiphuret of filver, or vitreous filver-ore, p, 4.S8. It 
is very brittle in general; the purer varieties are"(lightly 
malleable, its colour is a dull grey ; which by expofure 
becomes black. Under the blowpipe it leaves a metallic, 
button ; which is of a grey colour, in confequence of the 
iron contained id it. Contains copper 78-50, fulphur 
18-50, iron 2-25, filex 0-75. This is a very rich ore of 
copper ; but not eafily reduced, on account of the fulphur 
contained in it. It is met with principally in Siberia, 
Sweden, Saxony, and in Cornwall; the laft-mentioned 
place affords the moft-diftinftly cryftallized fpecimens. 
A confiderable quantity of this ore has lately been reco¬ 
vered from the ref life of feveral old mines in Cornwall, 
which were worked feventy or eighty years fince ; the va¬ 
luable nature of this ore not being known there, at tha£ 
time. It is commonly accompanied by yellow fuiphuret 
of copper, or mundie. Grey fuiphuret of copper may 
be diftinguiftied from the difcoloured varieties of red- 
copper ore, in not effervefcing'with nitric acid ; from fui¬ 
phuret of filver, by its brittlenefs, and by the grey co¬ 
lour of the metallic button which it leave? after the ac¬ 
tion of the blowpipe. 
. 32. Cuprum phlogifticum, bituminous copper, or pitch- 
ore : black, burning fiovvly with a flame, and at Lift con- 
fuming to alhes. Found in Daiecarlia in Sweden, and in- 
Siberia; refembles a piece of coal or bituminous (hift • it 
confilts of bituminous coal or (hale impregnated with- 
oxyd of copper ; the ore is extr.ifted from the allies with 
confiderable difficulty. • , • 
Plate III. fig. 1, is a piece of native copper from Hun¬ 
gary ; it is arborelcent, furnilhed as it were with buds and 
leaves, but covered with a greenifli cruft which hides the 
6 K real 
