Correspondence regarding Arc of Meridian work, triangulation and geodesy, divided into the following sections:

'Correspondence with Surveyor-General's Department Cape Town': letters relating to D. Gill's annual reports and the geodetic survey, 1898-1900.

'Completion of African Arc of Meridian': letters of 1898-1899, including D. Gill's application to the Royal Geographical Society for assistance in completing a geodetic survey of South Africa from South to North along the 30th Meridian.

'Proposed Survey of Lake Tanganyika': letters of 1898-1899, including a letter from G.H. Darwin to D. Gill regarding their cooperation on the survey.

'Bailey's Survey', 1896-1899.

'Triangulation of Egypt, 1896-1897.

'Requests for known Latitudes and Longitudes', 1897-1900.

'West African Longitudes', 1898-1899.

'Geodetic Survey of South Africa. Requests for copies of Dr Gill's Report', 1896-1900, including a copy of the report and reactions to it.

'Miscellaneous', 1887-1900, including copies of T. Maclear's requests to the Admiralty for financial assistance in carrying out Lacaille's Arc of Meridian, 1861; material on the erection of beacons on the south-west coast; requests for information from individuals; and survey work details.