Screw bolt of 4 in length and 0.75 in diameter with nut 1.75 in sq x 0.75 in salvaged (c.1974) during re-conditioning of the Avon Viaduct (OSGR: NS 9816 7695) on the Edinburgh to Glasgow Union Canal erected 1820 (Engineer: Hugh Baird). The bolt fastened cast iron plates together to form part of the aqueduct trough.
The aqueduct is 250 m long and 26 m high. It is the longest and tallest aqueduct in Scotland. It is the second longest in Britain after the Pontcysyllte Aqueduct in Wales.