Prior to the British [[Industrial Revolution]] there were small-scale industries scattered throughout Wales. These ranged from those connected to agriculture, such as milling and the [[Wool industry in Wales|manufacture of woollen textiles]], through to mining and quarrying. Agriculture remained the dominant source of wealth. The emerging industrial period saw the development of copper smelting in the [[Swansea]] area. With access to local coal deposits and a harbour that connected it with Cornwall's copper mines in the south and the large copper deposits at [[Parys Mountain]] on Anglesey, Swansea developed into the world's major centre for non-ferrous metal smelting in the 19th century. The second metal industry to expand in Wales was iron smelting, and iron manufacturing became prevalent in both the north and the south of the country. In the north, [[John Wilkinson (industrialist)|John Wilkinson]]'s Ironworks at [[Bersham]] was a major centre, while in the south, at [[Merthyr Tydfil]], the ironworks of [[Dowlais Ironworks|Dowlais]], [[Cyfarthfa Ironworks|Cyfarthfa]], Plymouth and [[Penydarren Ironworks|Penydarren]] became the most significant hub of iron manufacture in Wales. By the 1820s, south Wales produced 40% of all Britain's [[pig iron]].