Dated 1862-1874. From Working papers and experimental observations relating to optics including polarisation, photometry, spectra and the characteristics of light, [1840-1875].

Notes on the colouration of various compounds, including correspondence between George Gabriel Stokes (1819-1903), Lucasian Professor of Mathematics, University of Cambridge, and Charles Wheatstone, especially listing publications on the subject of colour, 1862-1873; descriptions of experiments involving the combination of colours, 1874; observations on salts of cobalt and chromium in solution; sulphates and chlorides of copper; reflective qualities of transparent liquids and crystals; observations on the optical properties of films on metallic plates; effects of coloured films on the base of a prism; experiments involving fluorescence; papers entitled 'miscellaneous observations on colours', including the spectra of metals in solution and under combustion, experiments to measure absorption employing gelatine, and pre-Newtonian theories of colour.