A—FURNACE. B—FOREHEARTH. C—OBLONG MOULDS.
placed apart by themselves, of which one basketful is mixed with the precious
thorns to be re-melted. The exhausted liquation cakes are “dried” at the
same time as other good exhausted liquation cakes.
placed apart by themselves, of which one basketful is mixed with the precious
thorns to be re-melted. The exhausted liquation cakes are “dried” at the
same time as other good exhausted liquation cakes.
The thorns which are drawn off from the lead, when it is separated from
silver in the cupellation furnace34, and the hearth-lead which remains in the
crucible in the middle part of the furnaces, together with the hearth material
which has become defective and has absorbed silver-lead, are all melted
together with a little slag in the blast furnaces. The lead, or rather the
silver-lead, which flows from the furnace into the fore-hearth, is poured out
into copper moulds such as are used by the refiners; a centumpondium of
such lead contains four uncíae of silver, or, if the hearth was defective, it
contains more. A small portion of this material is added to the copper and
lead when liquation cakes are made from them, if more were to be added
the alloy would be much richer than it should be, for which reason the wise
silver in the cupellation furnace34, and the hearth-lead which remains in the
crucible in the middle part of the furnaces, together with the hearth material
which has become defective and has absorbed silver-lead, are all melted
together with a little slag in the blast furnaces. The lead, or rather the
silver-lead, which flows from the furnace into the fore-hearth, is poured out
into copper moulds such as are used by the refiners; a centumpondium of
such lead contains four uncíae of silver, or, if the hearth was defective, it
contains more. A small portion of this material is added to the copper and
lead when liquation cakes are made from them, if more were to be added
the alloy would be much richer than it should be, for which reason the wise