| RefNo | Title | Date |
| MS/373/1/43 | Letter from Lord Salisbury, Downing Street, to [Thomas Edward] Thorpe | 17 May 1902 |
| NLB/14/285 | Copy letter from Joseph Lister, to the Most Honorable Marquis of Salisbury [Robert Arthur Talbot Gascoyne-Cecil], Fellow of the Royal Society | 9 February 1897 |
| NLB/15/160 | Copy letter from Robert William Frederick Harrison, to the Marquis of Salisbury [Robert Arthur Talbot Gascoyne-Cecil], Fellow of the Royal Society | 7 July 1897 |
| NLB/17/421 | Copy letter from Michael Foster, to The Marquis of Salisbury [Robert Arthur Talbot Gascoyne-Cecil], Arthur James Balfour, Joseph Chamberlain, George Joachim Goschen, Sir John Eldon Gorst, the Duke of Devonshire [Spencer Compton Cavendish], the Earl of Halsbury [Hardinge Stanley Giffard], and Viscount Richard Assheton Cross | 27 October 1898 |
| NLB/16/792 | Copy letter from Michael Foster and Arthur William Rucker, to the Marquess of Salisbury, H.M. Secretary of State for Foreign Affairs | 7 June 1898 |
| NLB/20/356 | Copy letter from Arthur William Rucker and Michael Foster, to Robert Arthur Talbot Gascoyne-Cecil, Marquis of Salisbury | 30 March 1900 |
| MS/928/2/77 | Signature of Lord Salisbury, collected by Charles Vernon Boys | n.d. |
| IM/005599 | Swinton, Alan Archibald Campbell | 1896 |
| MC/8/438 | Letter from Jas [James] Alderson, 17 Berkeley Square, to Sir Edward Sabine, President of the Royal Society | 1 November 1869 |
| MC/8 | Volume 8 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1867-1869 |
| MC/16/20 | Letter from Hugh Cecil, 20 Arlington Street, to the Royal Society | 16 March 1893 |
| HS/24/177 | Copy letter, from Sir John Herschel to Robert A. T. Gascoyne-Cecil, dated at Collingwood | 26 November 1866 |
| ACS/6/1/15 | X-Ray negative of the hand of Robert Arthur Talbot Gascoyne-Cecil, Lord Salisbury, taken by Alan Archibald Campbell Swinton | 1896 |
| RSC/5/2/7 | Letter from Lord Salisbury, Foreign Office, to Mr [John] Gwyn Jeffreys | 21 January 1879 |