EMAP_2012_Report_6_1.pdf (7.3 MB) - The Heritage Council

hearth cakes are generally bun or palm sized (Photos-Jones et al. 2010, lxvii). In addition
amorphous smaller fragments known as smithing slag lumps are also regularly found
(Wallace & Anguilano 2010b, 76).
Analysis of the huge assemblage of metallurgical residues from Clonfad indicated that the
refining of bloom produced larger smithing hearth cakes which may have originally have been
classified as the product of smelting (Young 2009a, 8.1). This view was based on chemical
analysis of the cakes and would mean that many earlier assemblages interpreted as the result
of smelting would have to be looked at again. The analysis suggests that at Clonfad residues
for smelting were minimal and that this must have taken place elsewhere. Other specialists
do not believe that bloom smithing creates large cakes of slag and would attribute them to
smelting (Photos-Jones et al. 2010, lxvii). The evidence from sites such as Johnstown 1 can
be viewed in terms of a large quantity of bloomsmithing carried out alongside smelting
(Photos-Jones 2008a).
Micro metallurgical debris known as hammerscale is an important indicator of smithing. This
is an oxidised film of metal produced as bloom is hammered and indicates the presence of
the anvil (Wallace & Anguilano 2010b, 71). Different types of smithing produce different
shapes and flakes are thicker during bloomsmithing and thinner where artefacts are being
forged (Young 2012, 3). Evidence for ‘hammerscale’ has been identified at least nine sites
within the EMAP 2012 gazetteer, including within structures at Killickaweeny and Sallymount
(Photos-Jones 2008b, 22-23; Clarke & Long 2009, 46). Given that this material is highly
mobile after its deposition its presence has to be viewed alongside other evidence. The
remains of a building close to a smithing site could contain hammerscale even if it was not
directly associated with metallurgy.
Bellows and tuyères were used iron-working as well as in non-ferrous metalworking. They are
thought by many specilialists to have been used in smithing and smelting (Wallace &
Anguilano 2010b, 71). It has also been suggested that they were only employed in smithing
hearths although their occurrence in the remains of furnaces requires further investigation
(Young 2010). The bellows rarely survive but clay tuyère fragments are frequently identified.
Examples of these – used in either ferrous or non-ferrous metal-working – have been
recorded at 36 sites within the EMAP 2012 gazetteer in varying quantities and states of
preservation (Appendix 1). Comber notes three types, small clay tubes, larger clay tubes and
perforated conical disks perhaps designed to protect bellows (Comber 2008, 117). Some
commentators prefer the term air-pipes as tuyère is used to describe nineteenth-century
blast-furnace technology (Photos-Jones et al. 2010, cxxvii). Excavations in recent years have
found relatively intact examples at Clonfad where they were typically 140mm across and
26mm in diameter (Young 2009a, 8.1) while at Lowpark they were 140-150mm in diameter
with and inner bore width of 25mm (Wallace & Anguilano 2010c, 9-10). The large quantities
of vitrified clay fragments at Lowpark and pieces of tuyères found indicate substantial wellinsulated
smithing hearths with clay wall superstructures and blow holes (Wallace &
Anguilano 2010b, 75). At Lisanisk four complete examples were found which were built in coil
form with the blowhole possibly made by wrapping it around a wooden block and then air
dried rather than fired (Photos-Jones et al. 2010, lxxxix). It was suggested that an added
layer of clay and straw would be added to the block to increase porosity. Other complete
examples are known but not recorded in detail from Ballycasey More (O’ Neill 2003b). There
is evidence that stones were used to strengthen the sides of the hearth underneath the
tuyère as at Clonfad (Young 2009a, 15). At this site a distinctive type of slag was identified as
resulting from close association with the tuyère. This was termed the pro-tuyère tongue and
developed on the lower edge of the tuyère (ibid.). These long tuyères were fed to the centre
of a wide hearth for smithing.
A growing number of anvils have been identified on Irish early medieval settlements. A stonebuilt
clay-lined smithing hearth was found at Clogher hillfort associated with two ‘bowl’
furnaces and a flat rectangular limestone block, interpreted as an anvil (Edwards 1990, 88).
Another large stone with a flat working surface was found in close proximity to an iron-
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