| RefNo | Title | Date |
| EC/1846/22 | Armstrong, William George, Baron Armstrong of Cragside: certificate of election to the Royal Society | |
| IM/000131 | Armstrong, William George, Baron Armstrong of Cragside | 1887 |
| NLB/1/27 | Copy letter from Michael Foster, to Sir William George Armstrong | 1 December 1885 |
| MC/14/168 | Copy of a letter from John Evans, The Royal Society, to Sir William [George] Armstrong | 13 November 1886 |
| NLB/1/268 | Copy letter from John Evans, to Sir William George Armstrong, Fellow of the Royal Society | 17 November 1886 |
| NLB/1/415 | Copy letter from John Evans, to Sir William George Armstrong, Fellow of the Royal Society | 3 March 1887 |
| NLB/1/402 | Copy letter from John Evans, to Sir William George Armstrong | 18 February 1887 |
| NLB/1/398 | Copy letter from John Evans, to Sir William George Armstrong | 10 February 1887 |
| NLB/6/542 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 30 May 1892 |
| NLB/6/992 | Copy letter from Herbert Rix, to Messrs Harrison & Sons | 29 September 1892 |
| NLB/6/523 | Copy letter from Herbert Rix, to Mr Collings | 27 May 1892 |
| NLB/6/997 | Copy letter from Herbert Rix, to Messrs Harrison & Sons | 30 September 1892 |
| NLB/6/635 | Copy letter from Herbert Rix, to Lord William George Armstrong | 18 June 1892 |
| NLB/6/774 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 12 July 1892 |
| NLB/6/669 | Copy letter from Herbert Rix, to Lord Kelvin [William Thomson] | 23 June 1892 |
| NLB/6/632 | Copy letter from Herbert Rix, to Reverend Henry William Watson, Fellow of the Royal Society | 20 June 1892 |
| NLB/6/659 | Copy letter from Herbert Rix, to Lord Kelvin [William Thomson], President of the Royal Society | 23 June 1892 |
| NLB/6/660 | Copy letter from Herbert Rix, to Sir John Evans, Treasurer, Royal Society | 23 June 1892 |
| NLB/6/657 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 23 June 1892 |
| NLB/6/667 | Copy letter from Herbert Rix, to Professor William Edward Ayrton | 23 June 1892 |
| NLB/6/1029 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 6 October 1892 |
| NLB/6/993 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 29 September 1892 |
| NLB/6/714 | Copy letter from Herbert Rix, to Professor William Edward Ayrton | 1 July 1892 |
| NLB/6/762 | Copy letter from Herbert Rix, to Captain Andrew Noble, Fellow of the Royal Society | 9 July 1892 |
| NLB/6/950 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 24 September 1892 |
| NLB/6/967 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 27 September 1892 |
| NLB/6/949 | Copy letter from Herbert Rix, to Lord William George Armstrong | 24 September 1892 |
| NLB/6/991 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 29 September 1892 |
| NLB/6/1201 | Copy letter from Herbert Rix, to Michael Foster | 9 November 1892 |
| NLB/7/145 | Copy letter from Herbert Rix, to Lord William George Armstrong | 10 December 1892 |
| NLB/7/141 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 9 December 1892 |
| NLB/7/752 | Copy letter from Herbert Rix, to Lord William George Armstrong | 19 April 1893 |
| NLB/7/701 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 12 April 1893 |
| NLB/8/1017 | Copy letter from Herbert Rix, to Lord Armstrong, Fellow of the Royal Society | 10 February 1894 |
| NLB/11/102 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 20 April 1895 |
| NLB/11/4 | Copy letter from Herbert Rix, to Reginald Hawthorn Hooker, Royal Statistical Society, 9 Adelphi Terrace, Strand, W.C. | 2 April 1895 |
| NLB/11/308 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 29 May 1895 |
| NLB/11/329 | Copy letter from Herbert Rix, to Lord Rayleigh [John William Strutt] | 5 June 1895 |
| RR/7/242 | Referee's report by William George Armstrong, on a paper 'On the durability and preservation of iron ships, and on riveted joints' by William Fairbairn | 10 July 1873 |
| IM/000126 | Armstrong, Wlliam George, Baron Armstrong of Cragside | nd |
| NLB/1/276 | Copy letter from John Evans, to Sir William George Armstrong | 20 November 1886 |
| NLB/6/577 | Copy letter from Herbert Rix, to Lord Kelvin [William Thomson], Fellow of the Royal Society | 3 June 1892 |
| NLB/11/341 | Copy letter from Herbert Rix, to Lord William George Armstrong, Fellow of the Royal Society | 7 June 1895 |
| PP/20/16/1 | Printed proof, 'On a multiple induction machine for producing high tension electricity, and on some remarkable results obtained with it' by William George Armstrong | 1892 |
| PP/20/16 | Paper, 'On a multiple induction machine for producing high tension electricity, and on some remarkable results obtained with it' by William George Armstrong | 1892 |
| PP/20/16/2 | Figures, multiple induction machine and dust figures by William George Armstrong | 1892 |
| MC/14/167 | Letter from [William George] Armstrong, Cragside Rothbury, to [John] Evans | 12 November 1886 |
| MC/14/170 | Letter from [William George] Armstrong, Cragside, Morpeth, to [John] Evans | [18] November 1886 |
| MC/14/172 | Letter from [William George] Armstrong, Cragside, Morpeth, to [John] Evans | 21 November 1886 |
| MC/14/96 | Letter from [Sir William George] Armstrong, Cragside Morpeth, to the Royal Society to Sir [Andrew] Noble | 28 December 1885 |
| MC/14 | Volume 14 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1885-1888 |