furnace, vaulted with unbaked bricks, is similar to an oven, and also to the
cupellation furnace, in which the lead is separated from silver, which I described
in the last book. The crucible is made of ashes, in the same manner as
18In this enrichment of copper by the " settling " of the silver in the molten mass the
original copper ran, in the two cases given, 60 ozs. 15 dwts and 85 ozs. 1 dwt. per ton. The
whole charge weighed 2,685 lbs., and contained in the second case 114 ozs. Troy, omitting
fractions. On melting, 1,060 lbs. were drawn off as " tops," containing 24 ozs. of silver, or
running 45 ozs. per ton, and there remained 1,625 lbs. of "bottoms," containing 90 ozs. of
silver, or averaging no ozs. per ton. It will be noticed later on in the description of making
liquation cakes from these copper bottoms, that the author alters the value from one-third
librae, a semi-uncia and a drachma per centumpondium to one-third of a libra, i.e., from no ozs.
to 97 ozs. 4 dwts. per ton. In the Glossary this furnace is described as a spleisofen, i.e., a
refining hearth.
