ABSTRACT
When Columbus discovered the New World, not more than half a dozen metals were known to Man. Now he has isolated all 70 of them and also ‘ constructed ’ a number of new ones, such as plutonium and neptunium, which previously did not exist in nature. Some of these metals may never be of use to the engineer, either because they have no desirable physical properties or because they ‘ corrode ’ far too readily – some instantaneously on exposure to the atmosphere. Nevertheless, who would have thought, even as late as the 1950s, say, that by the end of the twentieth century we would have used samarium and neodymium (in magnets), hafnium (in nuclear plant), yttrium and lanthanum (in high-temperature alloys) and erbium (in cancer therapy generators)?
