A close acquaintance of the famous engineer, Chantrey created several busts of James Watt between 1814 and 1816. The present version may have been copied from one of the plaster replicas available in his workshop. With its herm bust it corresponds to the marble now in the Scottish National Portrait Gallery (inv. no. PG 1186). The letter 'G' in the inscription, however, is unexplained as James Watt is not known to have carried a middle name.