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Steelyards are portable ‘scales with beam arms of unequal length’ (Crummy 1983, 99), rather than being an equal-arm balance. They therefore had a fulcrum close to one end, or more specifically two; the material being weighed (the load) was suspended via a loop at the terminal of the same end, often in a pan, or from a double hook attached below a (steelyard) weight (Brailsford 1964, 78; fig. 40, no. 11). They worked when a counterweight was moved along a graduated scale on the longer beam arm, the weight being measured when equilibrium was reached. The beam arm with the two fulcrums had two loops for use for hanging, one either side; one loop was closer to the terminal than the other. These loops allowed for weighing in two scales, by turning the steelyard over and hanging it by the other hook; the hook closer to the terminal allowed for far heavier items to be weighed. The presence of these three loops at one end of the arm, and their asymmetrical configuration, is distinctive.
‘Steelyard’ is the name acquired by such balances, which may be based on the name of the sample yard of the Merchants of the Hanse in medieval and early post-medieval London, the Steelyard (Shortt 1968, 66). However, most examples recorded by the PAS are Roman. They were used for weighing relatively large objects, anything up to multiple modern kilograms, either domestically or commercially (Crummy 1983, 99).
PAS object type(s) to be used
Weights for use with steelyards found separately can be recorded under STEELYARD WEIGHT
As noted, most steelyards recorded by the PAS are Roman, where such balances were termed staterae. An example, discussed below, was found in Colchester in a 1st-century Boudiccan destruction level, but evidence from archaeological finds and the iconography of steelyard weights shows that they endured throughout the Roman period. They reappeared in the 13th century, with medieval examples commonly dating to the years around 1300 (Cherry in Saunders and Saunders ed. 1991, 47).
Roman steelyards have the three loops at a widened end of the arm, as referred to in the introduction. A terminal loop is for the suspension, via a chain, of a load via a hook connected to a weight (Barford, Blockley and Day 1984, 397; fig. 10) or a pan (Crummy 1983, 99-100; fig. 104). The other loops are set one on each side of the widened beam arm, one closer to the terminal loop than the other. Both of these loops would have retained suspension hooks (Crummy 1983, 99-100; fig. 104). The longer, narrower beam arm had a terminal expansion, either integral or attached separately, to prevent the counterweight falling off. This beam arm was marked in graduations on each narrow edge that corresponded with the side loops. On an example found in Colchester, the side corresponding to the side loop furthest from the terminal loop was graduated effectively in Roman ounces, with each uncia (27.29 g) denoted by a punched dot (Crummy 1983, 99-100; fig. 104). On the same side, a groove replaced every twelfth dot to represent a Roman pound, or libra (327.45 g). The opposing side, corresponding to the side loop closest to the terminal loop, was graduated entirely in libra, each pound represented apparently in a combination of transverse grooves and Roman numerals. The other sides can also be marked with details relating to the weight; that from Colchester with the letter ‘S’ at intervals for the half pounds, or semis (167.73 g).
Steelyard weights are discussed in detail in their own guide, but lead examples are often biconical, with an iron loop at each end; copper-alloy cased steelyard weights can be of elaborate anthropomorphic and other forms.
These are unlikely to be recorded by the PAS; an example from Huish, Wiltshire, was of composite iron and wood construction (Cherry in Saunders and Saunders ed. 1991, 47).
Post-medieval steelyards have a thinned tab at the widened end of the arm, perforated for the suspension hooks and the load arrangement, rather than having projecting loops (e.g. NARC-B23C36).