, t 305 3 
CXpofed to the flame by themfelveS, th^y uHll 
found inftantly to melt, and part of their fuiphuf 
to go off y the copper may afterwards be obtained 
in two ways : the one, by keeping the proof in 
fufion for about a minute, and after fuffering it to 
€ool ^ when it will be found to have a dark and 
uneven appearance externally, but which, after 
being broken difcovers the metallic copper of a 
globular form in its centre, furrounded with a re^ 
gule, which flill contains fome fulphur and a por 
tion of the metal : the other, by being melted 
with borax, which iafl way fometimes makes th^ 
metal appear foonen 
SECT. XLII. 
The Minerce cupri pyritace^^ containing coppef^ 
fulphur, and iron, may be tried v/ith the blow-*, 
pipe, if they are not too poor : in thefe experi- 
ments the ore ought to be calcined, and, after 
tha4 the iron fcorified. For this purpofe a bit of 
the ore mufl; be expofed to a flow flame, that as, 
much of the fulphur as poiTible may part from it^ 
before it is melted, becaufe the ore commonly melta 
very foon, and then the fulphur is more difficult 
to drive off. After being melted, it mufl be kept, 
in fufion v/ith a ftrong fire, for about a minute^ 
that a great part of the iron may be calcined : and, 
after that, Ibme botax mufl: be added, which 
fcorlfies the iron, and turns with it to a black 
flag. If the ore is very rich, a metallic copper 
will be had in the flag, after the fcorification : if 
the ore is of a moderate richnefs, the copper will 
flill retain a little fulphur, and fometimes iron ; the 
produ6l will therefore be brittle, and mufl: with 
great caution be feparated from the flag, that it 
mny not break into pieces and if this producl is 
> ' X after- 
