Referee's report by Thomas Romney Robinson, on a paper 'On the spectra of ignited gases and vapours, with especial regard to the different spectra of the same elementary gaseous sub­stance' by Julius Plücker Recommended for publication in the 'Philosophical Transactions of the Royal Society'. The researches have confirmed some of the conclusions previously arrived at by the referee. Refers to work by John Hall Gladstone, A Miller [?], Heinrich Johann Wilhelm Geissler, Daniël Ruhmkorff and John Peter Gassiot. Subject: Physics and Chemistry [Published in the Proceedings of the Royal Society of London, 1864] 4 April 1864