Undated ink drawing of Fraunhofer's solar spectrum.

General correspondence concerning optics, relating mainly to telescopes, 1884-1894, including two copies of the Admiralty Telescope Contract, 1884; a copy of Patent No. 17994 of 1892: 'Improvements in Compound Object Glasses for Telescopes' by H.D. Taylor; W.J. Watson on increasing the power of a telescope; D.F. Webster on the reflection of the Moon in a mirror; Ralf Sadler on improvements to object glasses; and W.H. Duncan on water telescopes.

General correspondence concerning telescopes, etc., 1893-1900, including R. Sadler on object glasses; G.G. Stokes on the need for guiding telescopes in astrophotography; G.H. Lastrie on the rules of triangulation and horizon distances; and J.C. Beltingham on the theory of vision in a telescope.

Papers and correspondence concerned mainly with the testing of telescopes, 1888-1892, including a file of correspondence on the testing of Royal Navy telescopes and binoculars; Dr Parsons on evidence of eye power increasing with use; and an undated memorandum by the Astronomer Royal concerning a convertor for the 28" telescope.

File of correspondence on navigation, 1892-1894, including J. Bannister on the history of navigation; Captain Straker on the distance and bearings of distance lights; and H.D. Paine on a device for correcting the error of compasses.