« Reply #1 on: Friday 11 July 08 16:10 BST (UK) »
The furnaces and vessels for holding the molten metal would be lined with fireclay or firebricks. A mason would be employed to install this lining and to repair it as it wore and burned away.
Otherwise he might just have been doing building work or repairs.

Morton, Leiper, Donaldson, Hamilton, Balantyne, Torrance, Steel, Wilson, Young, Smith, all from Ayrshire/Lanarkshire, Scotland
Pearce, Day, Chiddy, Kingdon, Dunn: Southern England
Darbyshire: Lancashire
Derbyshire, Owen, Jones : N Wales
Beatty, Lannon: Waterford, Ireland