New Sources for Reconstructing the Discovery of Potassium and Sodium: Manuscripts and Letters relating to their Electrical Detection, Isolation, Naming, Announcement, and Publication by Humphry Davy

This paper revisits the very well-known episode of Humphry Davy's electrical detection, isolation, naming, announcement, and publication of potassium and sodium. His initial experiments were made in the basement laboratory of the Royal Institution during the autumn of 1807. This paper draws on recently digitised Davy manuscripts as well as two letters (published as an appendix) written by the medical student Henry Holland to his father at the end of November 1807 which all provide significant new insights into this episode. The letters also illustrate the sociability and clubbable mores of the scientific and medical communities. Taken together these sources tell a complex story of the issues involved surrounding Davy's results, what the nature of the new substances were and what they should be named (the evolution of their names has not been previously discussed) and, perhaps, most strikingly, how the new metals might be interpreted in terms of phlogiston theory. But beyond that, I interpret Davy's discovery of potassium and sodium as part of a long continuum of his approach to chemical and geological research and theory, rather than, as most of the historical literature portrays, an isolated but important event.