A set of correspondence entitled 'Cape Observatory and Survey 1855 to 1870 July', divided into eight sections:

General correspondence and papers regarding the Cape Observatory and Cape Survey, 9 April 1855 - 20 July 1870, comprised largely of correspondence between T. Maclear and G.B. Airy. There are letters regarding Encke's Comet; general reports on Observatory business; letters on the Cape Survey; a printed copy of 'Observations of Zenith Distances with the Transit Circle, 1855'; observations of Donati's Comet; observations made with the transit circle; a set of Bessel's refraction tables; and a letter of 10 January 1870 asking Maclear to agree to retire.

Correspondence regarding the appointment of computers.

Correspondence concerning instruments at the Cape Observatory, with a drawing of the reflector of the Cape Transit Circle. There are also reports on the Hardy Transit Clock and a bill from F. Dent for repairs to the clock, 9 June 1857, together with details of a Sheepshanks Clock purchased in October 1858.

Correspondence between T. Maclear, G.B. Airy and the Admiralty on the Cape Survey, including a copy of Maclear's report on the 'Geography and Topography of the Cape of Good Hope', 9 March 1857.

A letter from T. Maclear to G.B. Airy regarding the ordering of geodetic instruments, 23 June 1857; tables comparing the sector and mural circle observations; and correspondence regarding these observations.

Correspondence on the printing of the Cape Survey work and the Arc of the Meridian, including an index by G.B. Airy.

Correspondence concerning the distribution of T. Maclear's work on the Arc of the Meridian, 1867.

A request from G.B. Airy for a comparison to be made between his history of the Cape Observatory and details in the Board of Longitude's letters.