Brass . 
105 
spread about with constant stirring till the whole was cons 
verted into a reddish oxyd, somewhat cohering, and shew- 
ing the appearance of copper approaching to reduction* 
The 400 pounds were increased hereby to 425 pounds 2 
ounces, making an increase of above six and one-fourth 
on 100. 
Next, 800 lbs. of fresh metal were melted on a rever- 
beratory, and the 425 lbs. 2 ounces of oxyd were added 
to it with constant stirring for about twenty minutes* 
The fire was continued for nine hours with occasion- 
al stirring of the metal, and samples were drawn 
from time to time, which shewed a gradual approach 
in the melted metal to the state of pure copper. As the 
refining took place at the surface of the fluid metal, or the 
point of contact between it and the scoriae, the metal was 
there purer than at the bottom. Nine hours after the melt- 
ing of the metal the copper beneath tile scoriae was fine* 
red, and fibrous, and was then run off into moulds. The 
scoriae remained in, for half an hour longer to melt out 
part of the metal entangled in it, which was then let out, 
and lastly, the scoriae itself was raked out, which was a 
black and pasty mass, that hardened excessively when 
cold, and still contained some copper entangled in its 
substance. The results of this operation were 761 lbs. 
12 ozs. of copper run into the moulds ; 46 lbs. of copper 
sweated out of the scoriae, and 7 lbs. 4 ounces of small- 
grained copper, samples, See. or in total 915 lbs. of copper 
from 1200 of metal, or nearly 68 from 100. The scoriae 
weighed 474 lbs. and when thoroughly bruised in a 
stamping mill, and washed, it gave 18 lbs. more of copper. 
Thus then by this simple process nearly 70 parts (in 
all) of very good copper may be got from 100 parts of 
metal, whose known contents of copper are about 80 
per cent. 
VoL. HI, 
O 
