II 
Copper . 
phur, it is better not to perform the whole reduction in a 
single operation, but first to separate the metallic oxyd 
after dephlagration (which may be done by washing) and 
then to reduce it by a proper flux. 
The reduction of the pure oxyds or carbonated oxyds 
of copper, whether natural or artificial, is effected without 
loss, and is by far the best method, simply by heating in- 
tensely in contact with charcoal in a covered crucible.— 
This is in fact a very close imitation of the method of re- 
duction in the large way of the roasted copper ores, only 
as these latter still contain sulphur, arsenic, iron, and other 
foreign matters, the process requires to, be repeated many 
times before the copper is in a pure malleable state, in 
each of which, the impurities separate in the form of a 
thick pasty scum, as already described, under the article 
of reduction in the large way. 
In small experiments, where saline fluxes are used, 
these impurities dissolve in the flux (which is one of the 
great uses of these substances) and one or at most two 
operations, will suffice. 
When copper is pure (that is, of a saleable purity, for 
it is very rarely found absolutely pure) it is soft, malle- 
able, and of a beautiful brilliant yellow- red where recently 
cut or filed. On the contrary, when containing sulphur, 
arsenic, or iron, it is black, dense, sonorous, brittle, and 
more of a vitreous than a truly metallic appearance. In 
this state it is called copper-matt or black copper by me- 
tallurgists. Subsequent melting in contact with air, or 
with fluxes, removes these impurities, and if the operation 
be judiciously performed, the loss sustained by the matt, 
in being converted into pure copper is principally that of 
the impurities ; for it is a valuable property of this metal 
to be much less easily oxidated, scorified, and dissolved 
by sulphurets, than any of the metals with which it is 
usually found mixed, and particularly than iron. 
After all, however, the analysis of copper ores in the dry 
