Building
Cupellation hearth
Silver was refined from lead by cupellation: the lead was heated under a blast of air in a shallow hearth lined with bone ash, so that lead and base metals oxidised and were absorbed or skimmed off, leaving silver. In the 12th century silver from the lead mines around Alston fed the mint that Henry I founded at Carlisle after 1122. Refining analysis of northern coins confirms cupellation was standard practice.
Caveats (confidence: medium)
Details of 12th-century hearth construction in England are not recorded in the sources consulted; bone-ash lining is the standard method but not confirmed here.
Sources: cumbriacountyhistory.org.uk · ora.ox.ac.uk
Built from
- Cupellation hearth
Made here
- Cupel lead for its silver