Correspondence with C. Pritchard concerning shutters for the solar photographic work, 1892.

Correspondence with A. Arnath concerning the whereabouts of W. De La Rue's tables for the reduction of solar plates, 1894, including a letter to Mrs De La Rue on this subject, with a negative reply.

Letter to E.M. Autonaide, Paris, 1896, enclosing tables of sunspot areas for 1894-1895.

Correspondence with Lieutenant Colonel G. Gore concerning plates for solar photography at Dehra Dun, 1896.

Correspondence with D. Packer concerning the particulars of solar photographs and the use of metal plates, 1896.

Correspondence with Sir J.N. Lockyer concerning sunspot results and photographs, 1896.

Correspondence with Frank C. Dennett, who requests a print of a solar plate for publication, 1896.

Correspondence with Sir J.N. Lockyer concerning sunspot latitudes and their publication, 1898.

Correspondence with Herr T.F.H. Schultz concerning sunspot measures and his requests for prints and published articles, 1898.

Letters from James P. Hull, New York, 1900, requesting photographs for an article on the 1900 solar eclipse.

Correspondence with Sir J.N. Lockyer concerning sunspot measures and an apparent error, 1901.

Correspondence with J. McPherson, Newcastle, regarding a solar photograph he has sent for comment, 1901.

Correspondence with J. Eccles, who wishes to visit the Royal Observatory to see how the solar plates are measured, 1901.

Correspondence with H.H. Turner, Oxford, concerning sunspot measures and errors, and requesting the Royal Observatory's observations, 1905.

Correspondence with William Fitzgerald, Croydon, who sends a solar photograph for comment, 1905.

Correspondence with Senor Salvatore Raurich of Barcelona, who sends two photographs for comment and requests copies of the Royal Observatory's prints, 1905.

Correspondence with the Royal Alfred Observatory, Mauritius, concerning solar photography, 1892-1907. The letters include correspondence with Mr Mairson and Sir J.W. Swan regarding suitable plates for use on Mauritius, a letter concerning the plates required to complete the Royal Observatory records, and correspondence on the deficiencies in the Mauritius plates and suggested remedies.

Correspondence and related papers concerning a query as to the inclination of the wires in the Dehra Dun photoheliograph and their orientation, 1908-1912.