The Black Palmer—dubbed with black copper coloured peacock's harl, and a black cock's hackle over that, wings, blackbird.
Hence it appears that there may be several different sorts of black copper.
The refining of this black copper is performed in a kind of reverberatory furnace.
The same method is adopted for taking out the black copper in successive layers.
The black copper oxide is reduced to reddish metallic copper by the carbon monoxide, which is thereby changed to carbon dioxide.