Heavy metals are here treated as light metals and, in general, are not further considered. The heaviness of naturally occurring metals such as gold, copper, and iron may have been noticed in prehistory and, in light of their malleability, led to the first attempts to craft metal ornaments, tools, and weapons. All metals discovered from then until 1809 had relatively high densities; their heaviness was regarded as a singularly distinguishing criterion. From 1809 onwards, light metals such as sodium, potassium, and strontium were isolated. Their low densities challenged conventional wisdom and it was proposed to refer to them as "metalloids" (meaning "resembling
British Non-Ferrous Metals Research Association British Non-Ferrous Metals Research Association The British Non-Ferrous Metals Research Association was a research group in the United Kingdom during the 20th century, bringing together public and privately funded research into metallurgy. The name was abbreviated officially to B.N.F.M.R.A. (the organisation was normally known as ‘The BNF’ during its life). It was formed in 1920 by members of the British Non-Ferrous Metals Federation which represented the commercial interests of British manufacturers of coppers and copper alloys, lead, zinc and other non-ferrous metals and their alloys, latterly including titanium. Robert Hutton was appointed director in 1921. The 600 or so subscribing