This is a large piece of a cast block of copper slag dating to around 1760 (the white and brown markings are superficial and recent). This block shows characteristic bubbling and swirls where the molten metal cooled, as well as patches of iridescense (top left of close-up, bottom left of front). Although damaged around the edges, its parallel front and back allow measurement of its width (pictured with the bubbling), which varies between 195mm 200mm, indicating an original specification of a maximum 8 inches.
The blocks were cast by filling moulds with the waste products of the smelting works at Crew's Hole, an industrial operation that was owned in the mid 18th century by William Reeves who lived in what is now Arnos Manor Hotel, Bath Road. Reeves used them to build what was originally his stables and offices and is now known as The Black Castle public house, Junction Road, a grade 1 listed building.
Similar blocks can be seen in many parts of Brislington, as well as further afield, particularly as rounded triangles used as coping stones on the top of walls, and rectangular building blocks are also found. It would be interesting to know just how great a quantity of this waste material was recycled into a unique and occasionally beautiful building material that has clearly stood the test of time.
Material: metal
Period: Post Medieval
Find spot: Hampstead Road, Brislington, Bristol. ST 612710