'Greenfield Bras Mills, near Holywell, Flintshire', Wales, 1792.

Coloured engraving by W C Wilson after an original drawing by J Ingleby. The presence of abundant fast-flowing water and reserves of copper ore combined to make the Greenfield Valley in Flintshire, north-east Wales, one of the earliest cradles of industrialisation in Britain. From 1766 onwards, the mills in the valley produced copper and bras utensils, many of which were shipped from Liverpool to West Africa, where they were traded for slaves who were then transported to America and the West Indies.