FLUX. 
.752 
2. Earthy; 3. Inflammable; and 4. Metallic. 
As the subject, however, is treated at consi- 
derable length, we shall refer the reader to 
Mr. Bergman’s writings, and confine our- 
selves in this place to what he has advanced 
concerning the last of these subjects, namely, 
metallic substances. 
r l he perfect metals, when calcined (oxyge- 
nated) in the moist way, recover their former 
nature by simple fusion.* The imperfect metals 
ate calcined by fire, especially by the exterior 
flame ; and then, in order to their being re- 
duced, indispensably require the contact of an 
inflammable substance. With respect to fu- 
sibility, the two extremes are mercury and 
platina; the former being scarcely ever seen 
in a solid form, and the latter almost as diffi- 
cult of fusion. The metals, therefore, may 
be ranked in this order, according to their de- 
grees of fusibility. 1. Mercury; 2. Tin; 3. 
Bismuth; 4. Lead; 5. Zinc;* 6. Antimony; 
7. Silver; 8. Gold; 9. Arsenic; 10. Cobalt; 
11. Nickel; 12. Iron; 13. Manganese; 14. 
Platinum. The last two do not yield to the 
blowpipe, and indeed forged iron does not 
melt without difficulty; but cast iron per- 
fectly. 
Metals in fusion affect a globular form, 
and easily roll off the charcoal, especially 
when of the size of a grain of pepper. Smaller 
pieces, therefore, ought either to be used, or 
they should rest in hollows made in the char- 
coal. On their first melting they assume a 
polished surface, an appearance always re- 
tained by the perfect metals; but the imper- 
fect are soon obscured by a pellicle formed of 
the calx (oxide) of the metal. The colours 
communicated by the calces varv, according 
to the nature of the metal from which the calx 
is produced. Some of the calces easily re- 
cover their metallic form by simple exposure 
to flame upon the charcoal; others are re- 
duced in this way with more difficulty; and 
some not at all. The reduced calces of the 
volatile metals immediately fly off from the 
charcoal. In the spoon they exhibit globules ; 
but it is very difficult to prevent them from 
being first dissipated by the blast. 
The metals are taken up by the fluxes; 
but as soda yields an opaque spherule, it is 
not to be made use of. Globules of borax 
dissolve and melt any metallic calx; and, un- 
less too much loaded with it, appear peilucid 
and coloured. A piece of metal calcined in 
flux produces the same effect, but more 
slowly. A portion of the calx generally re- 
covers its metallic form, and floats on the 
melted matter like one or more excrescences. 
The calces of the perfect metals are re- 
duced by borax in the spoon, and adhere to 
it at the point of contact, and there only. 
The microcosmic salt acts like borax, but 
does not reduce the metals. It attacks them 
more powerfully on account of its acid na- 
ture ; at the same time it preserves the sphe- 
rical form, and therefore. is adapted in a pe- 
culiar manner to the investigation of metals. 
The tinge communicated to the flux fre- 
quently varies, being different in the fused 
and in the cooled globule ; for some of the 
dissolved calces, while fused, show no colour, 
but acquire one while cooling; but others, 
on the contrary, have a much more intense 
colour while in the state of fluidity. Should 
the transparency be injured by too great a 
concentration of colour, the globule, on com- 
pressing it with the forceps, or drawing it out 
into a thread, will exhibit a thin and transpa- 
rent mass; but if the opacity arises from su- 
persaturation, more flux must be added ; and 
as the fluxes attract the metals with unequal 
forces, the latter precipitate one another. 
Metals when mineralized by acids have 
the properties of metallic salts ; when mine- 
ralized by carbonic acid, they possess the pro- 
perties of calces, that volatile substance being 
easily expelled without any effervescence ; 
but when combined with sulphur they possess 
properties of a peculiar kind. They may 
then be melted, or even calcined upon the 
charcoal, as also in a golden or silver spoon. 
The volatile parts are distinguished by the 
smell or smoke; the fixed residua, by the 
particles reduced or preeip tated upon iron, 
or from the tinge of the fluxes. 
Gold in its metallic state fuses on the char- 
coal, and is the only metal which remains 
unchanged. It may be oxygenated in the 
moist way by solution in aqua regia; but to 
calcine it also by fire, we must pursue the 
following method: To a globule of micro- 
cosmic salt, let there be added a small piece 
of solid gold, of gold leaf, purple mineral, 
or, which is best of all, of the crystalline 
salt formed by a solution of gold in aqua 
regia containing sea-salt. Let this again 
be melted, and added while yet soft to tur- 
bith mineral, which will immediately grow 
red on the contact. The fusion being after- 
wards repeated, a vehement effervescence 
arises; and when this is considerably dimi- 
nished, let the blast be stopped for a few mo- 
ments, again begun, and so continued until 
almost all the bubbles disappear. After this 
the spherule, on cooling, assumes a ruby co- 
lour; but if this does not happen, let it be 
just made soft by the exterior flame, and 
upon hardening, this tinge generally appears. 
Should the process fail at first, owing to some 
minute circumstances which cannot be de- 
scribed, it will succeed on the second or thitd 
trial. The ruby-coloured globule, when com- 
pressed by the forceps while hot, frequently 
becomes blue; by sudden fusion it. generally 
assumes an opal colour, which by refraction 
appears blue, and by reflection of a brown 
red. If further urged by the tire it loses all 
colour, and appears like water; but the red- 
ness may be reproduced several times by the 
addition of turbith mineral. The flux is red- 
dened in the same manner by the addition 
of tin instead of turbith ; but it has a yellow- 
ish hue, and more easily becomes opaque; 
while the redness communicated by turbith 
mineral has a purple tinge, and quite resem- 
bles a ruby. Borax produces the same phe- 
nomena, bat more rarely ; and in all cases 
the slightest variation in the management of 
the fire will make the experiment fail en- 
tirely . 
The ruby colour may also be produced by 
copper; whence a doubt may arise, whether 
it is the gold or the remains of the copper 
that produce this effect. Mr. Bergman 
thinks it probable that both may contribute 
towards it, especially as copper is often found 
to contain ggkl. 
This precious metal cannot directly be 
mineralized by sulphur; but by the medium 
ot iron is sometimes formed into a golden 
pyrites. Here, however, the quantity of 
gold is so small, that a globule can scarcely be 
extracted from it by the blowpipe. 
Grains- of native platinum are not affected 
by the blowpipe, either alone or mixed 
with fluxes; which, however, are frequently 
tinged green by it: but platinum, precipitated 
from aqua regia by vegetable or volatile al- 
kali, is reduced by microcosmic salt to a 
small malleable globule. Our author has 
been able to unite seven or eight of these 
into a malleable mass; but more of them 
produced only a brittle one. Platinum scarcely 
loses all its iron, unless reduced to very thin 
fusion. 
Silver in its metallic stale easily melts, and 
resists calcination. Silver leaf fastened by 
means ot the breath, or a solution of borax, 
may easily be fixed on it by the flame, and 
through the glass it appears of a gold colour; 
hut care must be taken not to crack the glass. 
Calcined silv er precipitated from nitrous acid 
by fixed alkali is easily reduced. The mi- 
crocosmic acid dissolves it speedily and co- 
piously ; but on cooling it becomes opaque, 
and ot a whitish yellow, which is also some- 
times the case with leaf-silver. Copper is 
discovered by a green colour, and sometimes 
by that of a ruby, unless, we choose rather to 
impute that to gold. The globules can 
scarcelybe obtained pellucid, unless the quan- 
tity of calx is very small; but a longer fusion 
is necessary to produce an opacity with bo- 
rax. 1 he globule, loaded with dissolved 
silver during the time of Us fusion in the 
spoon, covers a piece of copper with silver, 
and becomes itself of a pellucid green: anti- 
mony quickly takes away the milky opacity 
of dissolved luna cornea, and separates the 
silver in distinct grains. Cobalt, and most 
ot the other metals likewise, precipitate silver 
on the same principles as in the moist way, 
viz. by a double elective attraction. This 
metal, when mineralized by marine and vi- 
triolic acids, yields a natural luna cornea, 
which produces a number of small metallic 
globules on the charcoal: it dissolves in 
microcosmic salt, and renders it opaque, and 
is reduced, partially at least, by borax. Sul- 
phurated silver, called also the glassy ore of 
that metal, fused upon charcoal, easily parts 
with the sulphur it contains; so that a polish- 
ed globule is often produced, which, if ne- 
cessary, may be depurated by borax. The 
silver may also be precipitated by the addi- 
tion of copper, iron, or manganese. When 
arsenic makes part of the compound, as in 
the red ore of arsenic, it must first be freed 
from the sulphur by gentle roasting, and 
finally entirely depurated by borax. It decre- 
pitates in the fire at first. 
Copper, together with sulphur and arsenic 
mixed with silver, called the white ore of 
silver, yields a regains having the same alloy. 
Galena, which is an ore of lead containing 
sulphur and silver, is to be freed in the same 
manner from the sulphur ; after which the 
lead is gradually dissipated by alternately 
melting and cooling, or is separated in *a 
cupel from the galena by means of the flame. 
Bergman lias not been able to precipitate 
the silver distinct from the lead, but the 
whole mass becomes malleable ; and the same 
is true of tin, but the mass becomes more 
brittle. 
Pure mercury flies off from the charcoal 
with a moderate heat, the fixed heteroge- 
neous matters remaining behind. When cal- 
cined, it is easily reduced and dissipated, and 
the fluxes take it up with effervescence ; but 
