The scums then settle down to the bottom of the cone, whence they are run off to the scum tank.
The lead is melted down slowly, when the impurities separate in the form of a scum (dross), which is easily removed.
I figured you'd be so busy defending the scum of the earth you wouldn't have a minute to spare.
Since the specific gravity of hot liquor is less than that of cold liquor, and since the specific gravity of the scum and particles of.
When kept fused in the presence of air lead readily takes up oxygen, with the formation at first of a dark-coloured scum, and then of monoxide PbO, the rate of oxidation increasing with the temperature.