| RefNo | Title | Date |
| NLB/26/463 | Copy letter from Robert William Frederick Harrison to, Major Percy Alexander MacMahon, Fellow of the Royal Society, Queen Anne's Mansions, S.W. | 25 March 1903 |
| EC/1890/08 | MacMahon, Percy Alexander: certificate of election to the Royal Society | |
| NLB/34/406 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 15 January 1907 |
| NLB/40/580 | Copy letter from Robert William Frederick Harrison to E W Knobel | 29 June 1909 |
| NLB/7/144 | Copy letter from Theodore E James, to Messrs Harrison & Sons | 10 December 1892 |
| NLB/7/179 | Copy letter from Herbert Rix, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Regency mansions, 40 Shaftesbury Avene, W.C. | 14 December 1892 |
| NLB/7/679 | Copy letter from Herbert Rix, to James Whitbread Lee Glaisher, Fellow of the Royal Society | 10 April 1893 |
| NLB/7/992 | Copy letter from Herbert Rix, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 13 June 1893 |
| NLB/7/731 | Copy letter from Herbert Rix, to Lord Rayleigh, [John William Strutt] | 14 April 1893 |
| NLB/7/1053 | Copy letter from Herbert Rix, to Major Percy Alexander MacMahon | 22 June 1893 |
| NLB/21/251 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, [Fellow of the Royal Society] | 10 October 1900 |
| NLB/10/336 | Copy letter from an unknown correspondent, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 10 November 1894 |
| NLB/7/1000 | Copy letter from Herbert Rix, to Dr James Whitbread Lee Glaisher, Fellow of the Royal Society | 14 June 1893 |
| NLB/10/312 | Copy letter from Herbert Rix, to Lord Rayleigh [John William Strutt], Secretary, Royal Society; Michael Foster; [Andrew Ainslie] Common; [Philip Lutley] Sclater; [Percy Alexander] MacMahon; and [Wilfred Hudleston] Hudleston | 7 November 1894 |
| NLB/18/551 | Copy letter from Arthur William Rucker, to Major MacMahon, Fellow of the Royal Society | 27 March 1899 |
| NLB/13/306 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 23 July 1896 |
| NLB/18/280 | Copy letter from Michael Foster, to [Major P] MacMahon | 16 February 1899 |
| NLB/12/171 | Copy letter from Herbert Rix, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 23 December 1895 |
| NLB/13/463 | Copy letter from Theodore E James, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Shaftesbury Mansions, 52 Shaftesbury Avenue, W. | 18 September 1896 |
| NLB/12/333 | Copy letter from Herbert Rix, to F A Eaton, Secretary, Royal Academy of Arts | 31 January 1896 |
| NLB/12/712 | Copy letter from Theodore E James, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 15 April 1890 |
| NLB/13/812 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 1 December 1896 |
| NLB/14/59 | Copy letter from Robert William Frederick Harrison, to the Secretaries of the Joint Permanent Eclipse Committee, Royal Astronomical Society, Burlington House, W. | 18 December 1896 |
| NLB/14/461 | Copy letter from Robert William Frederick Harrison, to J H Enthoven | 16 March 1897 |
| NLB/14/479 | Copy letter from Arthur William Rucker, to Professor Alfred George Greenhill, [Fellow of the Royal Society] | 17 March 1897 |
| NLB/14/480 | Copy letter from Robert William Frederick Harrison, to Professor Michael Foster, [Fellow of the Royal Society] | 17 March 1897 |
| NLB/14/721 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 3 May 1897 |
| NLB/17/569 | Copy letter from Robert William Frederick Harrison, to H R Tedder, Athenaeum Club, Pall Mall, S.W. | 21 November 1898 |
| RR/16/209 | Referee's report by George Ballard Mathews, on a paper 'Memoir on the theory of the partitions of numbers. Part III' by Percy Alexander MacMahon | December 1904 |
| RR/16/52 | Referee's report by Percy Alexander MacMahon, on a paper 'The differential invariants of a surface, and their geometric significance' by Andrew Russell Forsyth | 24 February 1903 |
| RR/16/208 | Referee's report by Edwin Bailey Elliott, on a paper 'Memoir on the theory of the partitions of numbers. Part III' by Percy Alexander MacMahon | December 1904 |
| RR/16/88 | Referee's report by Percy Alexander MacMahon, on a paper 'On a generalised Theory of Alternative Inheritance with special reference to Mendel's Laws' by Karl Pearson | 22 November 1903 |
| RR/17/198 | Referee's report by Andrew Russell Forsyth, on a paper 'Preliminary note on the operational invariants of a binary quantic' by Percy Alexander MacMahon | 31 October 1907 |
| RR/17/61 | Referee's report by George Ballard Mathews, on a paper 'Second memoir on the compositions of numbers' by Percy Alexander MacMahon | 18 September 1906 |
| RR/17/199 | Referee's report by Henry Frederick Baker, on a paper 'Preliminary note on the operational invariants of a binary quantic' by Percy Alexander MacMahon | [November 1907] |
| NLB/15/688 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 16 November 1897 |
| NLB/15/673 | Copy letter from Arthur William Rucker, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 15 November 1897 |
| NLB/15/695 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 18 November 1897 |
| NLB/15/785 | Copy letters sent from Robert William Frederick Harrison, to Professor Andrew Russell Forsyth, Fellow of the Royal Society | 10 December 1897 |
| NLB/15/863 | Copy letter from Robert William Frederick Harrison, to Professor George Howard Darwin, Fellow of the Royal Society, Newnham College, Cambridge | 4 January 1898 |
| NLB/18/90 | Copy letter from Robert William Frederick Harrison, to Major MacMahon, Fellow of the Royal Society | 13 January 1899 |
| NLB/18/87 | Copy letter from Robert William Frederick Harrison, to Major MacMahon, Fellow of the Royal Society | 10 January 1899 |
| NLB/18/106 | Copy letter from Robert William Frederick Harrison, to Professor A R Forsyth, Fellow of the Royal Society | 17 January 1899 |
| NLB/17/571 | Copy letter from Arthur William Rucker, to George Henry Darwin, [Fellow of the Royal Society] | 20 November 1898 |
| NLB/18/13 | Copy letter from Robert William Frederick Harrison, to Professor G H Darwin, Fellow of the Royal Society | 22 December 1898 |
| NLB/17/628 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 28 November 1898 |
| NLB/19/246 | Copy letter from Theodore E James, to Messrs Harrison & Sons | 19 July 1899 |
| NLB/20/459 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 27 April 1900 |
| NLB/18/645 | Copy letter from Robert William Frederick Harrison, to Major MacMahon, Fellow of the Royal Society | 14 April 1899 |
| NLB/19/313 | Copy letter from Robert William Frederick Harrison, to Sir Alfred Noble, Fellow of the Royal Society | 2 August 1899 |
| NLB/19/664 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 20 November 1899 |
| NLB/19/447 | Copy letter from Robert William Frederick Harrison, to Sir Andrew Noble, Fellow of the Royal Society | 5 October 1899 |
| NLB/19/480 | Copy letter from Robert William Frederick Harrison, to Sir Andrew Noble, [Fellow of the Royal Society] | 11 October 1899 |
| NLB/20/336 | Copy letter from Arthur William Rucker, to Percy Alexander McMahon, [Fellow of the Royal Society] | 26 March 1900 |
| NLB/20/335 | Copy letter from Arthur William Rucker, to Augustus Edward Hough Love, [Fellow of the Royal Society] | 26 March 1900 |
| NLB/21/283 | Copy letter from Robert William Frederick Harrison, to General C A [Percy Alecander] MacMahon, Fellow of the Royal Society | 19 October 1900 |
| NLB/20/612 | Copy letter from Theodore E James, to [Messrs Harrison & Sons] | 1 June 1900 |
| NLB/21/570 | Copy letter from Arthur William Rucker, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 11 December 1900 |
| NLB/21/361 | Copy letter from Arthur William Rucker, to Sir Percy Alexander MacMahon, Fellow of the Royal Society | 5 November 1900 |
| NLB/23/2/205 | Copy letter from Sir Michael Foster, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 3 June 1902 |
| NLB/34/387 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 11 January 1907 |
| NLB/38/753 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Chairman of the Scientific Relief Committee | 30 October 1908 |
| NLB/34/347 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 8 January 1907 |
| NLB/26/242 | Copy letter from the Secretaries of the Royal Society to, Major Percy Alexander MacMahon, Fellow of the Royal Society | 16 February 1903 |
| NLB/26/438 | Copy letter from Robert William Frederick Harrison to, Major Percy Alexander MacMahon, Fellow of the Royal Society, Winchester College | 20 March 1903 |
| NLB/26/763 | Copy letter from Robert William Frederick Harrison to, Major Percy Alexander MacMahon, Fellow of the Royal Society, Queen Anne's Mansions, Westminster, S.W. | 27 May 1903 |
| NLB/27/722 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 20 November 1903 |
| NLB/27/724 | Copy letter from Robert William Frederick Harrison, to Sir William Huggins, Major Alexander Percy MacMahon, Alfred Bray Kempe, and Dr Thomas Edward Thorpe, [Fellows of the Royal Society] | 20 November 1903 |
| NLB/27/767 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 27 November 1903 |
| NLB/29/6 | Copy letter from Joseph Larmor, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 14 June 1904 |
| NLB/34/440 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 23 January 1907 |
| NLB/28/547 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Queen Anne's Mansion, Westminster | 28 March 1904 |
| NLB/29/828 | Copy letter from Joseph Larmor, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 15 December 1904 |
| NLB/33/415 | Copy letter from Theodore E James, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 28 August 1906 |
| NLB/32/632 | Copy letter from Theodore E James, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 25 April 1906 |
| NLB/33/827 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 9 November 1906 |
| NLB/34/108 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 28 November 1906 |
| NLB/39/287 | Copy letter from Robert William Frederick Harrison to Major MacMahon | 22 December 1908 |
| NLB/36/549 | Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons | 12 November 1907 |
| NLB/34/488 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 29 January 1907 |
| NLB/35/625 | Copy letter from Robert William Frederick Harrison, to Major Percy MacMahon, Fellow of the Royal Society | 21 June 1907 |
| NLB/34/426 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 19 January 1907 |
| NLB/36/562 | Copy letter from Joseph Larmor, to Major Percy Alexander MacMahon, [Fellow of the Royal Society] | 14 November 1907 |
| NLB/36/756 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 11 December 1907 |
| NLB/37/558 | Copy letter from Robert William Frederick Harrison to Major P [Percy Alexander] MacMahon, Fellow of the Royal Society | 6 April 1908 |
| NLB/39/14 | Copy letter from Robert William Frederick Harrison to Major P [Percy Alexander] MacMahon, Fellow of the Royal Society | 13 November 1908 |
| NLB/41/182 | Copy letter from Robert William Frederick Harrison, to Professor Percy Alexander MacMahon, Fellow of the Royal Society | 28 October 1909 |
| NLB/44/553 | Copy letter from Robert William Frederick Harrison to Major P [Percy] A [Alexander] MacMahon FRS | 3 August 1911 |
| NLB/43/85 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 4 November 1910 |
| NLB/45/350 | Copy letter from Robert William Frederick Harrison to Major P [Percy] A [Alexander] MacMahon FRS, 6 Old Palace Yard, Westminster, SW | 19 February 1912 |
| NLB/42/798 | Copy letter from Robert William Frederick Harrison to Major P [Percy] A [Alexander] MacMahon FRS | 13 October 1910 |
| NLB/44/38 | Copy letter from Robert William Frederick Harrison to Major P [Percy] A [Alexander] MacMahon FRS | 26 April 1911 |
| NLB/45/833 | Copy letter from Robert William Frederick Harrison to Major P [Percy] A [Alexander] MacMahon FRS, Board of Trade, (Standards Department), Old Palace Yard | 17 May 1912 |
| NLB/47/408 | Copy letter from Robert William Frederick Harrison to Major P [Percy] A [Alexander] MacMahon FRS | 27 January 1913 |
| NLB/52/293 | Copy letter from [Robert William Frederick Harrison, Assistant Secretary of the Royal Society]; to Major Percy Alexander MacMahon, FRS | 3 November 1915 |
| NLB/52/461 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Major Percy Alexander MacMahon | 14 December 1915 |
| RR/17/62 | Referee's report by Henry Frederick Baker, on a paper 'Second memoir on the compositions of numbers' by Percy Alexander MacMahon | [October 1906] |
| RR/18/154 | Referee's report by Percy Alexander MacMahon, on a paper 'A silica standard of length' by George William Clarkson Kaye | 8 June 1911 |
| RR/18/153 | Referee's report by Percy Alexander MacMahon, on a paper 'Inbreeding in a stable simple Mendelian population with special reference to cousin marriage' by S M Jacob | 10 April 1911 |
| NLB/14/471 | Copy telegram from Robert William Frederick Harrison, to Professor Arthur William Rucker, [Fellow of the Royal Society] | [16 March 1897] |
| NLB/64/638 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to [Major Percy Alexander] MacMahon; FRS | 18 May 1923 |
| NLB/53/353 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 19 July 1916 |
| RR/25/27 | Referee's report by Ernest William Hobson, on a paper 'Contribution to the theory of attraction when the force varies as any power of the distance' by Percy Alexander MacMahon and H B C Darling | [August 1918] |
| NLB/58/37 | Copy letter from David Prain, Treasurer of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 3 March 1920 |
| RR/10/362 | Referee's report by Arthur Cayley, on a paper 'Memoir on symmetric functions of the roots of systems of equations' by Percy Alexander MacMahon | 12 March 1890 |
| RR/12/3 | Referee's report by Arthur Cayley, on a paper 'Memoir on the theory of the compositions of numbers' by Percy Alexander MacMahon | 21 December 1892 |
| RR/23/83 | Referee's report by Percy Alexander MacMahon, on a paper 'On the iteration of certain functions' by Ronald Ross | 18 October 1916 |
| RR/13/80 | Referee's report by Edwin Bailey Elliott on a paper 'Memoir on the theory of the partition of numbers. Part I' by Percy Alexander MacMahon | 17 June 1896 |
| RR/18/60 | Referee's report by Alfred Cardew Dixon, on a paper 'Memoir on the theory of the partitions of numbers. —Part V. Partitions in two-dimensional space' by Percy Alexander MacMahon | December 1910 |
| NLB/60/124 | Copy letter from Edwin Deller, Assistant Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 11 December 1920 |
| RR/18/82 | Referee's report by Percy Alexander MacMahon, on a paper 'The measurement of end-standards of length' by P E Shaw | 23 November 1910 |
| NLB/55/742 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 21 August 1918 |
| RR/12/5 | Referee's report by James Whitbread Lee Glaisher, on a paper 'Memoir on the theory of the compositions of numbers' by Percy Alexander MacMahon | 21 June 1893 |
| RR/12/196 | Referee's report by Andrew Russell Forsyth, on a paper 'A certain class of generating functions in the theory of numbers' by Percy Alexander MacMahon | 28 December 1893 |
| RR/17/318 | Referee's report by George Ballard Mathews, on a paper 'Memoir on the theory of the partition of numbers, part IV' by Percy Alexander MacMahon | July 1908 |
| RR/13/267 | Referee's report by Percy Alexander MacMahon, on a paper 'On the geometrical treatment of the 'normal curve' of statistics, with especial reference to correlation and to the theory of error' by W F Sheppard | 9 December 1897 |
| RR/13/81 | Referee's report by Edwin Bailey Elliott on a paper 'Memoir on the theory of the partition of numbers. Part I' by Percy Alexander MacMahon | 17 June 1896 |
| RR/14/62 | Referee's report by Edwin Bailey Elliott, on a paper 'Memoir on the theory of the partitions of numbers.—Part II' by Percy Alexander MacMahon | 21 December 1898 |
| RR/18/162 | Referee's report by Alfred Bray Kempe, on a paper 'Memoir on the theory of the partitions of numbers - Part VI' by Percy Alexander MacMahon | 28 June 1911 |
| RR/14/63 | Referee's report by George Ballard Mathews, on a paper 'Memoir on the theory of the partitions of numbers.—Part II' by Percy Alexander MacMahon | 16 January 1899 |
| RR/29/26 | Referee's report by Edmund Taylor Whitaker, on a paper 'On a class of transcendents of which the bessel functions are a particular case' by Percy Alexander MacMahon | June 1923 |
| RR/18/59 | Referee's report by George Ballard Mathews, on a paper 'Memoir on the theory of the partitions of numbers. —Part V. Partitions in two-dimensional space' by Percy Alexander MacMahon | December 1910 |
| RR/26/98 | Referee's report by Herbert William Richmond, on a paper 'The design of repeating patterns' by Percy Alexander MacMahon and W P D MacMahon | [November 1921] |
| NLB/57/429 | Copy letter from Sir Arthur Schuster, FRS Secretary of the Royal Society; to Major PA [Percy Alexander] MacMahon, FRS | 6 November 1919 |
| NLB/62/354 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 31 January 1922 |
| NLB/65/398 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 26 October 1923 |
| NLB/62/336 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 26 January 1922 |
| NLB/62 | New Letter Book volume 62, copy letters sent from Royal Society administration | 11 November 1921-10 June 1922 |
| RR/10/361 | Referee's report by James Joseph Sylvester, on a paper 'Memoir on symmetric functions of the roots of systems of equations' by Percy Alexander MacMahon | 4 March 1890 |
| NLB/64/750 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Major [Percy Alexander] MacMahon FRS | 14 June 1923 |
| NLB/70/296 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Major [Percy Alexander] MacMahon, FRS | 25 February 1927 |
| NLB/71/457 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Major [Percy Alexander] Machahon, FRS | 30 May 1928 |
| NLB/72/759 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [Henry Frederick] Baker, FRS | 4 April 1930 |
| NLB/64/751 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Horace] Lamb [Chairman of the Mathematics Committee] FRS | 14 June 1923 |
| NLB/10/524 | Copy letter from Herbert Rix, to Professor Michael Foster | 11 December 1894 |
| NLB/20/425 | Copy letter from Robert William Frederick Harrison, to Professor Andrew Russell Forsyth, Fellow of the Royal Society | 25 April 1900 |
| NLB/33/112 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Queen Anne's Mansions, S.W. | 29 June 1906 |
| NLB/35/828 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Chairman of the Scientific Relief Committee | 20 July 1907 |
| NLB/36/319 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 11 October 1907 |
| NLB/36/343 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 15 October 1907 |
| RR/13/79 | Referee's report by James Whitbread Lee Glaisher, on a paper 'Memoir on the theory of the partition of numbers. Part I' by Percy Alexander MacMahon | 8 June 1896 |
| RR/12/194 | Referee's report by Arthur Cayley, on a paper 'A certain class of generating functions in the theory of numbers' by Percy Alexander MacMahon | 28 November 1893 |
| RR/12/132 | Letter from Percy Alexander MacMahon, regarding a paper 'The differential covariants of twisted curves, with some illustrations of the application to quartic curves' by R F Gwyther | 17 November 1894 |
| RR/15/88 | Referee's report by Alfred Bray Kempe, on a paper 'Combinational analysis - the foundations of a new theory' by Percy Alexander MacMahon | 21 April 1900 |
| NLB/57/433 | Copy letter from Sir Arthur Schuster, Secretary of the Royal Society; to the Deputy Master of the Mint | [November 1919] |
| NLB/8/715 | Copy letter from Herbert Rix, to Professor Arthur Cayley, Fellow of the Royal Society | 13 December 1893 |
| NLB/10/1011 | Copy letter from Herbert Rix, to Professor Michael Foster | 25 March 1895 |
| NLB/12/335 | Copy letter from Herbert Rix, to Professor Michael Foster, Secretary, Royal Society | 31 January 1896 |
| NLB/34/881 | Copy letter from Archibald Geikie, to Major Percy Alexander MacMahon, Fellow of the Royal Society | 21 March 1907 |
| NLB/52 | New Letter Book volume 52, copy letters sent from Royal Society administration | 9 July 1915-8 March 1916 |
| NLB/57 | New Letter Book volume 57, copy letters sent from Royal Society administration | 27 June 1919-27 February 1920 |
| AP/76/3 | Unpublished paper, 'A memoir on the theory of order as defined by boundaries' by Edward J Dixon | 30 May 1904 |
| RR/12/130 | Referee's report by Percy Alexander MacMahon, on a paper 'The differential covariants of twisted curves, with some illustrations of the application to quartic curves' by R F Gwyther | 20 October 1894 |
| RR/12/195 | Letter from Andrew Russell Forsyth, to John William Strutt, 3rd Baron Rayleigh, regarding a paper 'A certain class of generating functions in the theory of numbers' by Percy Alexander MacMahon | 28 December 1893 |
| RR/15/87 | Referee's report by Edwin Bailey Elliott, on a paper 'Combinational analysis - the foundations of a new theory' by Percy Alexander MacMahon | May 1900 |
| AP/80/4 | Unpublished paper, 'On current curves' by R L [Richard Lionel] Hippisley | [1892] |
| AP/75/4 | Paper, 'Über Reihen auf der Convergenzgrenze' [On series at the limit of convergence] by Emanuel Lasker | 1900 |
| RR/12/4 | Letter from James Whitbread Lee Glaisher, to John William Strutt, 3rd Baron Rayleigh, regarding a paper 'Memoir on the theory of the compositions of numbers' by Percy Alexander MacMahon | 21 June 1893 |
| RR/13/76 | Referee's report by William Burnside, on a paper 'Memoir on the theory of the partition of numbers. Part I' by Percy Alexander MacMahon | 22 January 1896 |
| RR/13/77 | Letter from William Burnside, on a paper 'Memoir on the theory of the partition of numbers. Part I' by Percy Alexander MacMahon to the Secretary of the Royal Society | 31 January 1896 |
| RR/13/78 | Letter from James Whitbread Lee Glaisher, on a paper 'Memoir on the theory of the partition of numbers. Part I' by Percy Alexander MacMahon to the Secretary of the Royal Society | 8 June 1896 |
| RR/13/249 | Referee's report by Percy Alexander MacMahon, on a paper 'Mathematical contributions to the theory of evolution.— IV. On the probable errors of frequency constants and on the influence of random selection on variation and correlation' by Karl Pearson and Louis Napoleon George Filon | 9 December 1897 |
| RR/26/97 | Referee's report by Godfrey Harold Hardy, on a paper 'The design of repeating patterns' by Percy Alexander MacMahon and W P D MacMahon | [January 1922] |
| NLB/41/800 | Copy letter from Robert William Frederick Harrison, to Major Percy Alexander MacMahon, Fellow of the Royal Society, Deputy Warden of the Standards, Board of Trade | 1 March 1910 |