Correspondence on different aspects of the work of the Cape Observatory:
(1) Cape Observatory Instruments
Correspondence between G.B. Airy, W. De La Rue and D. Gill regarding the proposed large equatorial for the Cape, 10 April - 13 November 1880, with Airy's report to the Admiralty of 10 November 1880.
Correspondence between G.B. Airy and J. Simms regarding iron stands for small transits, including diagrams, 21-28 July 1880.
Correspondence between G.B. Airy and the Admiralty concerning a replacement micrometer for the Cape Observatory following the loss of its micrometer on the 'American' mail steamer, 31 July - 14 August 1880.
Correspondence between W.H.M. Christie, D. Gill, Capt. Wharton and J. Simms on the repolishing of the Cape Transit Circle object glass and replacing new micrometer screws, 13 October 1884 - 9 July 1885.
Correspondence between the Admiralty, W.H.M. Christie and D. Gill regarding the construction of a heliometer for the Cape Observatory, including detailed specifications, 3 April 1884 - 29 July 1884.
Estimates from G.M. Whipple for new magnetic instruments, March 1890.
Correspondence between W.H.M. Christie and R.H. Scott on the supply of magnetic equipment, November 1895.
Correspondence between the Admiralty and W.H.M. Christie concerning plans for a new building for the Cape Transit Circle, 9 August - 9 September 1897.
Correspondence between D. Gill and W.H.M. Christie regarding the testing of a photographic object glass, September 1897.
Correspondence between the Admiralty, F.W. Dyson and H. Spencer Jones on collimators of the transit circle and a microscope by Hilgers, 17 April 1901 - 10 April 1929.
(2) Cape Surveys
A copy of correspondence between D. Gill and Sir H. Bartle Frere on a survey of the Cape, 6 April 1880.
Correspondence relating to the examination of instruments to be used by Capt. Morris in his survey of Natal, 3 April - 6 May 1883.
(3) Cape Publications.
Correspondence between D. Gill, W.H.M. Christie, F.W. Dyson and members of other observatories regarding publications of the Cape Observatory, their distribution and requests for copies, 17 September 1891 - October 1900.
An article by H.S. Davies, reprinted from 'Science', on 'The Present State of Progress of the New Reduction of Piazzi's Star Observations', 13 April 1900.