Letter from Henry Enfield Roscoe, Owen's College, Manchester, to John Hall Gladstone Detailed letter reviewing his recent brief lecture on spectroscopy, noting the contributions of Bunsen and Kirchhoff. Roscoe explains the incompleteness of observations by Miller, Talbot and Wheatstone. Roscoe particularly referred to work by Gladstone and Brewster and showed copies of their diagrams. Discusses Kirchhoff's recent paper on absorbing sodium vapour published in the Philosophical Magazine. 10 May 1861