The brass industry was an important industry in Bristol. It supplied the African slave trade as much as local needs at home in Bristol and the surrounding areas. Emanuel Swedenborg in his 1734 book on brass, de Cupro, wrote that “The principal place where English brass is made is at Baptist Mills near Bristol”.
The raw materials were easily available. Brass is made from a mixture of copper and zinc. Copper ore (rock containing copper) was imported from nearby Cornwall and North Devon, and also from America. Baptist Mills was using 200 tons a year by 1712. A form of zinc was found on the Mendip Hills, in Somerset in 1566 and Bristol’s supplies came from there. The fuel used by the brass industry to heat the furnaces was coal, which came from the local coal mines at Kingswood, near Bristol. By 1712 the Bristol Brass & Copper Company works were using 2,000 cartloads of coal a week.