Correspondence concerning astrographic equatorials for the Greenwich and Cape observatories:

Official and unofficial correspondence with the Admiralty concerning the photographic mapping of the heavens, the transfer of the telegraphic wires to the Post Office, and the extra expense of re-determining the longitude between Paris and Greenwich telegraphically, 1887.

Official and unofficial correspondence with the Hydrographer of the Navy, A. Milner and Sir Howard Grubb concerning the photographic mapping of the heavens and a question about it asked in the House of Commons, 1887-1888.

Correspondence with the Admiralty and H.H. Turner concerning the order to Sir Howard Grubb to construct photographic telescopes, 1888.

Correspondence with the Admiralty regarding the payment for the photographic telescopes, 1889-1890.

Correspondence with Sir Howard Grubb concerning experiments and suggestions for the object glass, including a copy of a letter from Messrs Schott and Son on the employment of patent glass for photographic objectives, 1887-1888.

Correspondence with Grubb concerning arrangements for the payment and construction of an experimental object glass, with estimates for the production and erection of the photographic telescope, 1888.

Correspondence with Grubb accepting his tenders for telescopes for Greenwich and the Cape, and correspondence on the mechanical details of the instruments, 1888-1889.

Correspondence with Grubb concerned principally with optical matters, 1889-1890, including receipt of the 4" and 6" experimental object glasses and photographs taken with them.

Correspondence with Grubb concerning the charges for workmen's time, the division of the declination circle, the claim for the second instalment of the telescope for the Cape Observatory, and the dispatch of a telescope to the Royal Observatory at Greenwich, 1890.

Correspondence with Grubb giving details of the telescope for the Cape Observatory, a receipt for a 10" object glass and dark slide, and general correspondence on the mounting of the telescope and the dispatch to the Cape of the Cape Telescope, 1890-1891.