| RefNo | Title | Date |
| MS/377/1/82 | Letter from Rudolph Messel, 36 Mark Lane, London, to [William Fletcher Barrett] | 13 December 1877 |
| MS/377/1/86 | Letter from Rudolph Messel, 36 Mark Lane, London, to [William Fletcher] Barrett | 22 February 1878 |
| MS/377/1/84 | Letter from Rudolph Messel, 36 Mark Lane, London to [William Fletcher] Barrett | 17 January 1878 |
| MS/377/1/83 | Letter from Rudolph Messel, 36 Mark Lane, to William Fletcher Barrett, Royal College of Science, Dublin | 26 December 1877 |
| MDA/C/20 | Correspondence and papers on the Messel Fund | 1920-1964 |
| NLB/46/267 | Copy letter from Robert William Frederick Harrison, to Dr Rudolf Messel, Fellow of the Royal Society | 3 July 1912 |
| NLB/48/505 | Copy letter from Robert William Frederick Harrison, to Dr [Rudolf] Messel, Fellow of the Royal Society | 16 July 1913 |
| NLB/54/285 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Dr. [Rudolf] Messel, FRS | 21 March 1917 |
| NLB/61/670 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Henry Edward] Armstrong, FRS | 4 October 1921 |
| NLB/64/785 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Henry Edward] Armstrong, FRS. | 19 June 1923 |
| NLB/68/325 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Henry Edward] Armstrong, FRS | 18 June 1925 |
| MS/377/1/85 | Letter from Rudolph Messel, 36 Mark Lane, London, to [William Fletcher] Barrett | 11 February 1878 |
| EC/1912/09 | Messel, Rudolf: certificate of election to the Royal Society | |
| MDA/C/20/12 | Correspondence concerning the grave of Rudolf Messel | 1934-1938 |