Elegant Solutions. Philip Ball

that the new elements might be revealed in these enriched samples by the technique of spectroscopy. Elements irradiated by light re-emit some of the light in the form of distinct ‘spectral lines’ at specific wavelengths – this was how the element helium was discovered in 1868, when astronomers found previously unknown spectral lines in sunlight (the sun is rich in helium). But when the Curies gave their enriched samples to the French scientist Eugene Demarçay for analysis, he was unable to find any new spectral lines. There was still more purification to be done before the highly active elements would show themselves that way.

      This did not prevent the Curies from presenting their findings to the Institut de France in July, in a paper read by Becquerel. That month, they had chosen a name for one of the new elements they were sure the samples contained. ‘We thus believe’, they said, ‘that the substance we have extracted from pitchblende contains a metal never before known, akin to bismuth in its analytical properties. If the existence of this metal is confirmed, we propose to call it polonium after the name of the country of origin of one of us’. The paper’s title introduced another new word: ‘On a new radio-active substance contained in pitchblende.’