Unpublished paper, 'Experiments on the influence of magnetism on polarized light' by Carlo Matteucci Matteucci communicates some recent experiments on diamagnetism, and particularly on the influence of magnetism on polarised light. He uses an electromagnetic apparatus invented by [Heinrich Daniel] Rumkorf, consisting of a powerful electromagnet, of which the soft iron cylinder is traversed by a hole in the direction of the length of the axis, through which hole the ray of polarised light is made to pass; the voltaic current employed is that of seven pair of Grove’s construction. Annotations in ink throughout. Marked on front as 'To be printed in the Proceedings'. Subject: Physics / Magnetism / Optics Received 3 February 1848. Communicated by Sir John Frederick William Herschel. Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 5 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'Experiments on the influence of magnetism on polarized light'. 1848