Reverberatory Furnace

A smelting furnace in which the fuel and the ore being smelted are kept physically separate, with heat and flame from a coal fire reflected down onto the ore by the furnace's low arched roof — the technology that displaced the older ore hearth in British lead and copper smelting from the mid-18th century onward. Also known, especially in the Yorkshire Dales and Peak District lead fields, as a cupola.

Historical usage

First recorded in medieval glassmaking, the reverberatory furnace was adapted for metal smelting in Britain from around 1678, when Sir Clement Clerke and his son built cupolas in the Avon Gorge near Bristol; the first successful examples for lead and copper smelting followed near Bristol in the 1680s, with further lead cupolas built in Flintshire during the 1690s. The design spread through the 18th and 19th centuries across the Pennine and Peak District lead fields, at sites including the Duke of Devonshire's Cupola smelt mill on Grassington Moor, built in 1792 and worked until the mines there closed in 1882, and Derbyshire's Alport Cupola, built around 1840 and noted for the most complex surviving flue-condensing system of its kind in England.

How it worked

Coal was burned on a separate fire grate rather than in direct contact with the ore; the heat and flame were deflected down onto the ore, loaded onto a shallow hearth, by a low brick fire-bridge and the furnace's arched roof, which kept the coal smoke away from the metal while still concentrating enough heat to smelt it. At Grassington a smelting charge took around seven to eight hours to process, with the resulting molten lead collecting in a sump before being drawn off.

Why it was used

Unlike an ore hearth, a reverberatory furnace could burn ordinary mineral coal rather than the costlier charcoal or dried wood ('white coal') older methods needed, and, built of firebrick rather than a simple open hearth, could run for much longer at a controllable temperature — recovering more lead from a given quantity of ore, at lower fuel cost, than the ore hearth it replaced.

Regional variation

The name varied regionally even as the technology stayed essentially the same: 'cupola' was the everyday term in the Yorkshire Dales and Derbyshire lead fields, while 'reverberatory furnace' was the more formal, technical name used more widely across the industry.

Images

Mines associated with this term

Included only where MineArchive's own research gives a reasonable evidential basis — not every mine where this might plausibly apply.

• Alport Mines — Derbyshire (well documented example)
  The mine's own recorded history, workings and closure notes explicitly describe the Alport Cupola smelting works and its flue system.
• Grassington Moor Mines — North Yorkshire (well documented example)
  The mine's own recorded summary and history explicitly describe the Cupola smelt mill's coal-fired reverberatory ('cupola') furnaces.

Sources

1. (primary) Alport smelt mill, Harthill — Historic England (Scheduled Monument record)
2. (secondary) Smelting — Northern Mine Research Society
3. (secondary) The Cupola Smelt Mill — The Grassington Mines Appreciation Group

Record created: 24 August 2026 · Last researched: 24 August 2026