FLUX 
j it is soon totally driven off. When minera- 
lized by sulphur, it liquefies upon the charcoal, 
burns with a blue flame, smokes, and gradu- 
ally disappears; but, on exposing cinnabar to 
‘ the lire on a polished /piece of copper, the 
mercurial globules are fixed upon it all round. 
Lead in its metallic state readily melts, 
and continues to retain a metallic splendour 
for some time. By a more intense heat it 
boils and Smokes, forming a yd low circle 
upon the charcoal. It communicates a yel- 
I low colour, scarcely visible, to the fluxes; and 
I when the quantity is large, the globule, on 
I cooling, contracts more or less of a white 
[ opacity. It is not precipitated by copper 
I when dissolved ; nor do the metals precipi- 
1 tate it from sulphur in the same order as 
from the acids. When united to carbonic acid, 
it grows red on the first touch of the flame ; 
1 when the heat is increased it melts, and is re- 
1 -dueed to a multitude of small globules. When 
■united with phosphoric acid it melts, and 
yields an opaque globule, but is not reduced. 
| With fluxes it shows the same appearances as 
I oxide of lead. When mineralized by sulphur, 
lead easily liquefies, and being gradually de- 
I prived of the volatile part, yields a distinct 
! regains, unless too much loaded with iron. 
; It may be precipitated by iron and copper. 
A small piece of copper, either solid or 
| foliated, sometimes communicates a ruby co- 
j Jour to fluxes, especially when assisted by tin 
j or turbith mineral. If the copper is a little 
more or further calcined, it produces a green 
j pellucid globule, the tinge of which grows 
I weaker by cooling, and even verges towards 
i a blue. By long fusion with borax, the co- 
} lour is totally destroyed upon charcoal, but 
scarcely in the spoon. When once destroy- 
f ed, this colour can scarcely be reproduced 
1 by nitre; but it remains fixed with microcos- 
f mic salt. If the calx or metal to be calcined 
is added in considerable quantity during fu- 
sion, it acquires an opaque red on cooling, 
j though it appears green while pellucid and 
fused; but by a still larger quantity it con- 
j tracts an opacity even while in fusion, and 
j upon cooling a metallic splendour. Even 
when the quantity of copper is so small as 
] scarcely to tinge the flux, a visible pellicle is 
precipitated upon a piece of polished iron 
added to it during strong fusion, and the glo- 
bule in its turn takes the colour of polished 
j iron ; and in this way the smallest portions of 
copper may be discovered. The globule 
j made green by copper, when fused in the 
spoon with a small portion of tin, yields a 
spherule of the latter mixed with copper, 
j very hard and brittle : in this case the preci- 
! pitated metal pervades the whole of the mass, 
j and does not adhere to the surface. Cobalt 
I precipitates the calx of copper dissolved in 
] the spoon by a flux, in a metallic form, and 
1 imparts its own colour to glass, which nickel 
! cannot do. Zinc also precipitates it sepa- 
[ rately, and rarely upon its own surface, as we 
can scarcely avoid melting it. When miners - 
' lizedby the carbonic acid, copper grows black 
on the first contact of the flame, and melts in 
: the spoon ; on the charcoal the lower part, 
which touches the support, is reduced. With 
I 'a superabundance of marine acid, it tinges 
I the dame of a beautiful colour; but with a 
small quantity shows no appearance of the 
.metal in that way. Thus the beautiful crys- 
tals of Saxony, which are cubic, and of a 
deep green, do not tinge the flame, though 
VOL. I. 
they impart a pellucid greenness to micro- 
cosmic salt. An opaque redness is easily ob- 
tained with borax: but Mr. Bergman could 
not produce this colour with microcosmic 
salt. Copper simply sulphurated, when cau- 
tiously and gently roasted by the exterior 
flame, yields at last by fusion a regulus sur- 
rounded with a sulphurated crust. The mass 
| roasted with borax separates the regulus more 
quickly. 
If a small quantity of iron happens to be 
present, the piece to be examined must first 
be roasted, after which it must be dissolved in 
| borax, and tin added to precipitate the cop- 
! per. The regulus may also be obtained by 
sufficient calcination and fusion, even with- 
out any precipitant, unless the ore is very 
poor. When the pyrites contain copper, 
even in the quantity of the _ one-hundredth 
part of their weight, its presence may be de- 
tected by these experiments. Let a grain of 
pyrites, of the size of a flax-seed, be roasted, 
but not so much as to expel all the sulphur ; 
let it then be dissolved by borax, a polished 
rod of iron added, and the fusion continued 
until the surface when cooled loses all splen- 
dour. As much borax is required as will 
make the whole of the size of a grain of 
hemp-seed. Slow fusion is injurious, and 
the precipitation .is also retarded by too great 
tenuity; but this may be corrected by the 
addition of a little lime. Too much calcina- 
tion is also inconvenient ; for by this the glo- 
bule forms slowly, is somewhat spread, be- 
comes knotty when warm, corrodes the char- 
coal, destroys the iron, and tiie copper does 
not precipitate distinctly. This defect is 
corrected by a small portion of crude ore. 
When the globule is properly melted, ac- 
cording to the directions already given, it 
ought to be thrown into cold water immedi- 
ately on stopping the blast, in order to break 
it suddenly. If the copper contained in it 
is less than one-hundredth part, one end of 
the wire only lias a cupreous appearance, but 
otherwise the whole. 
Dr. Gahn has another method of examin- 
ing the ores of copper, namely, by exposing 
a grain of the ore, well freed from sulphur by 
calcination, to the action of the flame driven 
suddenly upon it by intervals. At those in- 
j stants a cupreous splendour appears on the 
| surface, which otherwise is black; and this 
splendour is more quickly produced in pro- 
portion as the ore is poorer. The flame is 
tinged green by cupreous pyrites on roasting. 
Forged iron is calcined, but can scarcely 
be melted. It cannot be* melted by borax, 
though it may by microcosmic salt, and then 
it becomes brittle. Calcined iron becomes 
magnetic by being heated on the charcoal, 
but melts in the spoon. The fluxes become 
green by this metal; but in proportion as the 
oxygen is more abuudant, they grow more 
of a brownish yellow. On cooling, the tinge 
is much weakened, and when originally weak, 
vanishes entirely. By too much saturation 
the globule becomes black and opaque. The 
| sulphureous pyrites may be collected into a 
i globule bv fusion, and is lirst surrounded by 
a blue flame; but as the metal is easily cal- 
cined, and changes into black scorin’, neither 
by itself nor with tluxes does it exhibit a're- 
gulus. It grows red on roasting. 
Tin easily melts before the blowpipe, and 
is calcined. The fluxes dissolve the calx 
.5 0 
sparingly; and when saturated, contract a 
milky opacity. Some small particles of this 
metal dissolved in any flux may be distinctly 
precipitated upon iron. Crystallized ore of 
tin, urged by fire upon the charcoal, yields 
its metal in a reguline state. 
Bismuth presents nearly the same appear- 
ances as lead ; the calx is reduced on the coal, 
and fused in the spoon. The calx, dissolved 
in microcosmic salt, yields a brownish yel- 
low globule, which grows more pale upon 
cooling, at the same time losing some of its 
transparency. Too much calx renders the 
matter perfectly opaque. Borax produces a 
similar mass in the spoon, but on the coal a 
grey one, which can scarcely be freed from 
bubbles. On fusion the glass smokes, and 
forms a cloud about tf. Bismuth is easily 
precipitated by copper and iron. Sulphurated 
bismuth is easily fused, exhibiting a blue 
flame and sulphureous smell. Cobalt, when 
added, .by means of sulphur, enters the glo- 
bule; but the scoria soon swells into distinct 
partitions ; which, when further urged by fire, 
throw out globules of bismuth. Sulphurated 
bismuth, by the addition of borax, may be 
distinctly precipitated by iron or manganese. 
Regulus of nickel when melted is calcined, 
but more slowly than other metais. The 
calx imparts an liyacinthine colour to fluxes, 
which grows yellow on cooling, and by long- 
continued fire may be destroyed. If the calx 
of nickel is contaminated by ochre of iron, 
the latter is first dissolved. Nickel dissolved 
is precipitated on iron, or even on copper; 
an evident proof that it does not originate 
from either of these metals. Sulphurated 
nickel is no where, found without iron and ar- 
senic: the regulus is obtained by roasting, 
and fusing with borax, though it still remains 
mixed with some other metals. 
Regulus of arsenic takes fire by a sudden 
heat, and not only deposits a white smoke on 
charcoal, but diffuses the same all around. 
The calx smokes with a smell of garlic, but 
does not burn. r | he fluxes grow yellow, 
without growing opaque, on adding a proper 
quantity of calx, which is dispelled by a long 
continuance of the heat. '1 his semimetal is 
precipitated in a metallic form by iron and 
copper, but not by gold. Yellow arsenic 
liquefies, smokes, and totally evaporates : 
when heated by the external flame, so as 
neither to liquefy nor smoke, it grows red, 
and yellow again upon cooling." When it 
only begins to melt, it acquires a red colour, 
which remains after cooling. Realgar lique- 
fies more easily, and is besides totally dissi- 
pated. 
Regulus of cobalt melts, and may partly 
be depurated by borax, as the iron is first 
calcined and taken up. The smallest portion 
of the caix tinges the flux of a deep-blue co- 
lour, which appears of a violet by refraction, 
and ; this colour is very fixed in tiie fire. Co- 
balt is precipitated upon iron from the blue 
globule, but not upon copper. When calx 
of iron is mixed with that of cobalt in a flux, 
the former is dissolved. This semimetal 
takes up about one-third of its weight of sul- 
phur in fusion, after which it can hardly be 
melted -again. It is precipitated by iron, 
copper, and several other metals. The com- 
mon ore yields an impure regulus by roast- 
ing. T he green cobalt, examined by our au- 
thor, tinges the microcosmic salt blue; but 
