Brass* 
106 
The second process was that with the assistance of 
black oxyd of manganese. 
In the same furnace 800 lbs. of bell-metal were first 
melted, and kept very hot, after which 25 lbs. of oxyd of 
manganese were thrown in, and the whole stirred and mix- 
ed with great care. Two hours after, 15 lbs. more of the 
manganese were stirred in, and the metal even then was 
sensibly purer than at first. This alternate addition of 
manganese, and stirring, continued till 100 lbs. of man- 
ganese were used, during which the metal constantly kept 
refining. Ten hours after the first melting, the copper 
was found to be soft, fibrous, and good, and was run off 
into moulds. It weighed 520 lbs. The scoriae was soft- 
er than the former, and not so well melted. It weighed 
344 lbs. and was still visibly rich in copper, as was prov- 
ed by after washing. The copper, exclusive of that in 
the scoriae, here amounted to about 60 from 100 of bell- 
metal. 
From these and many other experiments it appears 
that by very simple means from six to seven-eighths of the 
copper actually contained in bell-metal may be extract- 
ed ; and in particular circumstances this may be practise 
ed to advantage, but on the other hand the tin is lost to 
most economical uses, as its reduction from the state of 
an impure semi-vitrified scoriae is extremely difficult and 
expensive. [1 Aikin , 347, 
Copper with Iron . 
These only unite when the iron is in small quantity. 
The alloy is grey, hard, and somewhat brittle. 
Tutenag is a white aljpy of copper, zinc, and iron, ac- 
cording to Keir, which is very hard, tough, and sufficient- 
ly ductile to be wrought into various articles of furniture, 
such as candlesticks, &c. which take a high polish, and 
When made of the better sort of tutenag, are hardly distin- 
