Dated 1846-1875. From Working papers and experimental observations relating to optics including polarisation, photometry, spectra and the characteristics of light, [1840-1875].

Experimental and theoretical observations, chiefly concerning the polarisation of light, including experiments made with an electromagnet; striation in luminous tubes; a general description of absorption spectra; inventory of apparatus necessary to show the law of rotation of the plane of polarisation and outline description of polarising apparatus and polarimeter; consequences of the mixture of polarised light from different sources; notes on interference; criticism by Charles Wheatstone of then current theories to explain the phenomenon of aberration; experimental notes on the refraction of light through filters; proposal for a version of the telegraph able to utilise the phenomenon of optical polarisation; draft of paper 'Experiments on the Successive Polarization of Light with the Description of a new Polarizing Apparatus', published in the Proceedings of the Royal Society, 1871. With equations, sketches and chromatograms.