Correspondence of G.B. Airy and related papers under the heading 'Cape Observatory and Survey 1849 to 1854. Instruments', divided into thirteen sections:

Notes on the barometer used by Henderson.

Letters from G.B. Airy to W. Dolland regarding an eyepiece and level for the Cape Transit, 1850-1851.

Sir J. Herschel's recommendation for the erection of a transit circle at the Cape, 27 December 1851.

Correspondence with the Admiralty regarding the transit circle, including bills from Ransomes and Sims and Troughton and Simms for its construction, dated March 1853.

Correspondence with T. Maclear and W. Mann on the transit circle and fittings for it, plans of the Observatory and where the transit is to be placed, 4 March 1851 - 7 November 1854.

Correspondence with Ransomes and Sims concerning the transit circle.

Correspondence with W. Simms on the manufacture of an object glass for the transit circle.

Correspondence with Sir William Cubbitt on artificial stones for the Cape Transit Circle, 10 September - 7 October 1852.

Correspondence with Charles May regarding an artificial stone for the Cape Observatory.

Correspondence with J.B. White and others on artificial stones for the Cape, including a pamphlet on 'Experiments on the Strength of Portland and Roman Cements' by J. Bazley White and Sons, 1852.

Tradesmen's bills for work carried out in the preparation of the transit circle for the quarter ending 31 December 1852.

Correspondence on the return of Bradley's Zenith Sector, 18 December 1849 - 15 July 1850.

A copy of a letter from G.B. Airy requesting information on the Fuller Theodolite, 12 December 1851.