Photograph, experimental results by W C [William Chandler] Roberts-Austen A graph, labelled figure 3, comparing curves of pure gold, gold with 0.47% aluminium and gold with 0.5% lead. Subject: Metallurgy / Chemistry A print of this photograph was published in volume 49 of the Proceedings of the Royal Society alongside the paper 'On certain properties of metals considered in relation to the periodic law'. 22 January 1891