Correspondence with Troughton and Simms regarding the polishing of the transit circle object glass and the subsequent overhaul of the instrument, as well as the proposal to fit an aluminium dew cap to the transit circle, 1906.

Correspondence with Troughton and Simms on the improved illumination of the transit circle, 1908.

Correspondence with Troughton and Simms on the new travelling wire micrometer for the transit circle, including estimates, specifications, and the order and fitting of the new wire.

Miscellaneous notes on faults, damage and repairs to the transit circle and correspondence with S. Newcomb on the subject of refraction, 1875-1905.

Printed graph showing 'Latitude variations at Greenwich, 1911-1936, mean minus observed latitudes'.

Graph titled 'Parallax Error of Parallax plate'.

Tables of figures and graphs, 'Parallax Vol 2', 1927-1936.

Black and white photograph, probably taken on the site of the Royal Observatory, c. 1903. The photograph depicts a man standing behind a hollow concrete foundation and almost certainly relates to the building of the new transit circle.

Correspondence with Dr Schorr, Sir James Jeans and Major Levin regarding the specifications for the new transit circle, 1930-1931.

Correspondence with Sir Joseph Petavel, National Physical Laboratory, regarding the specifications for the glass circle on the new transit circle, 1933, including a report on the thermal coefficients of expansion of samples of glass, cast iron and gun metal.

Carbon copy of the conditions of contract for the manufacture and erection of the new transit circle, undated.

Correspondence between F.W. Dyson and the Admiralty requesting authorisation for the building of a new transit circle instrument and dome, 1929, including a confidential letter to the Board of Visitors on the same subject, of which there are three copies dated 26 May 1930.

Correspondence between H. Spencer Jones and T.W. Chalmers of 'The Engineer' magazine, 1936, concerning a request to visit the Royal Observatory, view the new transit circle and publish a description of it.

Correspondence between H. Spencer Jones and H.R. Lang of the 'Journal of Scientific Instruments' concerning a request for a detailed description of the new transit circle, 1936.

Correspondence with Dr W. Doberck on the new transit circle, 1936.

Black and white photograph of the new transit circle at the York works while undergoing tests, taken on the occasion of the visit of the British Association to York, September 1932.

Correspondence with J. Gray of Cooke, Troughton and Simms regarding cylindrical lenses and micrometers for the 3" transit circle, 1923.

Correspondence with Adam Huger Ltd on the testing of a new photoelectric cell at the Royal Observatory, 1925.

Memorandum from the Hydrographer of the Navy informing the Astronomer Royal that the lease on the site on Pole Hill of the North Meridian mark is to expire shortly and asking if a fresh lease is required, 1923 (the lease was allowed to expire and was not renewed).

Correspondence with J.F. Hellweg, United States Naval Observatory, recommending manufacturers of astronomical instruments, 1931.

Correspondence with A.F.C. Pollard on a new method of illuminating the crosswires of the transit circle, 1936.

Drawing (number 15) of a crosswire illuminator for a transit instrument, 1928.

Blueprint (number 1651) from Troughton and Simms Ltd of the 'Adjustable 'Y' block for East Pier' for the new transit circle, 1923.