For the whole of the eighteenth century and much of the nineteenth, a belt of coastal smelters--using local coals and ores from Cornwall, Cuba, and Chile--produced virtually all of Britain's copper, and much of the world's. Copper brought considerable wealth to Swansea, the center of the industry, and to several neighboring towns. But there was a price for the prosperity. The billowing clouds of toxic, foul-smelling smoke that copper production...