Some of the roasted ore is strewed upon it, and, after a quarter of an hour's working, the whole is taken out on the work-stone, where the lead produced runs off.
These are either roasted or exposed to the weathering action of the air.
The cut tobacco is now roasted, partly with the view of driving off mositure and bringing the material into a condition for keeping, but also partly to improve its smoking quality.
The charge of the retorts consists of a mixture of 1100 lb of roasted calamine and 550 lb of dry powdered coal per furnace.
