| Reference number | Title | Date |
| M/126 | Duddell Medal of the Physical Society | 1922 |
| M/204 | Duddell, William Du Bois CBE | 1917 |
| IM/001207 | Duddell, William | nd |
| RR/15/149 | Referee's report by Andrew Gray, on a paper 'The mechanism of the electric arc' by Phoebe Sarah Hertha Marks Ayrton | December 1901 |
| RR/15/180 | Second referee's report by George Carey Foster, on a paper 'The resistive and electromotive forces of the electric arc' by William Duddell | 7 February 1904 |
| NLB/23/1/698 | Copy letter from Robert William Frederick Harrison, to William Duddell, [Fellow of the Royal Society], 47 Hans Place, S.W. | 6 January 1902 |
| NLB/23/1/636 | Copy letter from Joseph Larmor, to William Duddell, [Fellow of the Royal Society] | 16 December 1901 |
| NLB/43/333 | Copy letter from Robert William Frederick Harrison, to William Duddell, Fellow of the Royal Society | 13 December 1910 |
| NLB/32/553 | Copy letter from Robert William Frederick Harrison, to William Duddell | 3 April 1906 |
| NLB/32/865 | Copy letter from Robert William Frederick Harrison, to William Duddell | 8 June 1906 |
| NLB/35/72 | Copy letter from Robert William Frederick Harrison, to William Duddell, 47 Hans Place, S.W. | 12 April 1907 |
| NLB/36/690 | Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons | 2 December 1907 |
| NLB/35/774 | Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons | 16 July 1907 |
| NLB/38/656 | Copy letter from Robert William Frederick Harrison, to William Duddell, Fellow of the Royal Society | 19 October 1908 |
| NLB/41/420 | Copy letter from Robert William Frederick Harrison, to William Duddell, Fellow of the Royal Society | 10 December 1909 |
| NLB/40/152 | Copy letter from Robert William Frederick Harrison to W [William] Duddell FRS | 26 April 1909 |
| NLB/41/589 | Copy letter from Joseph Larmor, to William Duddell, Fellow of the Royal Society | 18 January 1910 |
| NLB/45/143 | Copy letter from Robert William Frederick Harrison to W [William] Duddell FRS, 56 Victoria Street, SW | 5 January 1912 |
| NLB/46/145 | Copy letter from Robert William Frederick Harrison, to William Duddell, Fellow of the Royal Society | 17 June 1912 |
| NLB/47/141 | Copy letter from Robert William Frederick Harrison to W [William] Duddell FRS | 7 December 1912 |
| NLB/46/694 | Copy letter from Robert William Frederick Harrison, to William Duddell, Fellow of the Royal Society | 18 October 1912 |
| NLB/51/56 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society to William Duddell, FRS | 30 November 1914 |
| NLB/51/48 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society to William Duddell, FRS | 26 November 1914 |
| NLB/52/371 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor Charles Herbert Lees, Chairman of the Physics and Chemistry Committee and FRS | 19 November 1915 |
| RR/22/48 | Referee's report by William Duddell, on a paper 'The consumption of carbon in the electric arc. No. III - The anode loss' by W Geoffrey Duffield | 16 November 1915 |
| RR/21/50 | Referee's report by William Duddell, on a paper 'On the measurement of alternating electric currents of high frequency' by Albert Campbell and David William Dye | 30 June 1914 |
| RR/22/47 | Referee's report by William Duddell, on a paper 'The consumption of carbon in the electric arc. I - Variation with current and arc-length. II. - Influence upon the luminous radiation from the arc' by W Geoffrey Duffield | August 1915 |
| RR/15/179 | Referee's report by Professor Andrew Gray, on a paper 'The resistive and electromotive forces of the electric arc' by William Duddell | December 1901 |
| NLB/37/140 | Copy letter from Robert William Frederick Harrison to W [William] Duddell FRS | 30 January 1908 |
| RR/21/14 | Referee's report by William Duddell, on a paper 'On the flow of electricity through dielectrics, etc' by G E Bairsto | [June 1914] |
| EC/1907/11 | Duddell, William: certificate of election to the Royal Society | |
| NLB/36/883 | Copy letter from Robert William Frederick Harrison, to James Swinburne, Fellow of the Royal Society | 7 January 1908 |
| RR/15/178 | Referee's report by George Carey Foster, on a paper 'The resistive and electromotive forces of the electric arc' by William Duddell | 12 August 1901 |
| RR/15/181 | Referee's report by Arthur Schuster, on a paper 'The resistive and electromotive forces of the electric arc' by William Duddell | March 1904 |
| RR/21/15 | Committee report by William Duddell, on a paper 'On the flow of electricity through dielectrics, etc' by G E Bairsto | 26 November 1914 |