Alloyed with copper, zinc has been known for thousands of years in brass, but the metal itself is thought to have been isolated in India in the thirteenth century, and zinc coins were certainly used during the Ming Dynasty, which ran in China between 1368 and 1644. The Swiss alchemist, Paracelsus, knew of the metal, and it was identified as an element by the German chemist, Andreas Sigismund Marggraf, in 1746. In England, it was first produced on an industrial scale at the beginning of the eighteenth century.
Cadmium has a far shorter history than zinc, having been discovered in a sample of zinc carbonate by the German chemist, Friedrich Stromeyer, in 1817. But mercury has a lengthy past, being one of the seven metals (lead, tin, silver, gold, copper, iron and mercury) known to the ancients. The red sulphide, cinnabar, has long been used as a pigment, and mercury itself was of great interest to alchemists, who believed that it could somehow be used to turn base metals into gold. It was recognized as an element by Antoine-Laurent Lavoisier towards the end of the eighteenth century.
