I'll try and restate the problem.  I have an archaeological site report I am
working through.  There is no question that the site operated as a finery forge
during the last decade of the 18C and beginning of the 19C.  It is claimed,
based on cast iron artifacts found at the site and the slag that a cupola
foundry was also operated at the site.

The cast iron artifacts are primarily fragments of pigs, with some broken stove
plates, scrap, and a large failed casting.  These objects are exactly the kinds
of scrap one would expect to find at a finery forge.  The use of scrap is well
documented in the Knight family forges in the UK in the 1700s.

The cupola furnace appears to have been developed around 1794 by John Wilkinson
at Bersham, UK.  It seems unlikely to appear in the US at the same time.
The earliest depiction of a cupola furnace is an 1831 pamphlet on S. Wales. 
These are lightly built blast furnaces like those described by  Percy.  

 "When blast-furnaces are built slightly of brick only, and hooped or cased with
iron, they are usually designated cupola furnaces, to distinguish them from
massive furnaces..."  (Percy 1864:361-362).

 I have not found any earlier descriptions or depictions of cupola furnaces. 
What I have found are  reverberatory air furnaces, like that built at
Massaponax, VA by A Spotswood in the 1730s.  

The identification of the site as a foundry is also based on the slag.  But,
this was never subjected to other than visual analysis.  There is a great deal
of material in the literature on blast furnace, bloomery, and finery, and forge
slag.  I have been unable to locate information on foundry slags.  Could forge
slag be mistaken for foundry slag?

JH Brothers IV


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%