Unpublished manuscript, 'Description and purpose of the glass plate which bears the inscription "Interferenz-Spectrum. Longitudo et celeritas undularum lucis relativa cum in aere tum in vitro"' by Friedrich Adolph Nobert Nobert provides a physical description of the glass plate, which is 18 inches in length, 9 inches in breadth and 1.5 inches in thickness, with one polished side. He then describes the use of the plate in experiments. Includes one page of figures of the plate's use in experiments on light. Annotations in ink throughout. Subject: Scientific apparatus and equipment / Optics Received 16 April 1851. Communicated by Michael Faraday, with corrections in his hand. March 1851