| Reference number | Title | Date |
| EC/1902/09 | Hough, Sydney Samuel: certificate of election to the Royal Society | |
| NLB/38/630 | Copy letter from Robert William Frederick Harrison, to Sydney Samuel Hough, Fellow of the Royal Society | 14 October 1908 |
| NLB/40/792 | Copy letter from Robert William Frederick Harrison to Messrs Harrison & Sons | 21 August 1909 |
| NLB/16/168 | Copy letter from Arthur William Rucker, to S S Hough | 14 February 1898 |
| NLB/32/746 | Copy letter from Robert William Frederick Harrison, to [Messrs Harrison & Sons] | 19 May 1906 |
| NLB/32/275 | Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons, 46 St Martin's Lane, W.C. | 12 February 1906 |
| NLB/32/307 | Copy letter from Robert William Frederick Harrison, to [Messrs Harrison & Sons] | 17 February 1906 |
| NLB/32/318 | Copy letter from Robert William Frederick Harrison, to Sydney Samuel Hough, Fellow of the Royal Society, 88 Darenth Road, Stamford Hill, N | 19 February 1906 |
| NLB/40/198 | Copy letter from Robert William Frederick Harrison to Messrs Harrison & Sons | 30 April 1909 |
| NLB/44/392 | Copy letter from Robert William Frederick Harrison to S [Sydney] S [Samuel] Hough FRS, The Royal Observatory, Cape of Good Hope | 3 July 1911 |
| NLB/47/468 | Copy letter from Robert William Frederick Harrison to S [Sydney] S [Samuel] Hough FRS | 4 February 1913 |
| RR/13/49 | Letter from George Howard Darwin, on a paper 'The rotation of an elastic spheroid' by Sydney Samuel Hough to the Secretary of the Royal Society | 11 December 1895 |
| RR/13/50 | Referee's report by Augustus Edward Hough Love, on a paper 'The rotation of an elastic spheroid' by Sydney Samuel Hough | 20 December 1895 |
| RR/12/339 | Referee's report by Augustus Edward Hough Love, on a paper 'The oscillations of a rotating ellipsoidal shell containing fluid' by Sydney Samuel Hough | 21 February 1895 |
| RR/13/193 | Referee's report by Horace Lamb, on a paper 'On the application of harmonic analysis to the dynamical theory of the tides. — Part I. On laplace’s "oscillations of the first species” and the dynamics of ocean currents' by Sydney Samuel Hough | 3 April 1897 |
| RR/13/194 | Referee's report by George Howard Darwin, on a paper 'On the application of harmonic analysis to the dynamical theory of the tides. — Part I. On laplace’s "oscillations of the first species” and the dynamics of ocean currents' by Sydney Samuel Hough | 7 April 1897 |
| RR/13/196 | Referee's report by George Howard Darwin, on a paper 'On the application of harmonic analysis to the dynamical theory of the tides.—Part II. On the general integration of Laplace’s dynamical equations' by Sydney Samuel Hough | 24 October 1897 |
| RR/12/340 | Referee's report by Horace Lamb, on a paper 'The oscillations of a rotating ellipsoidal shell containing fluid' by Sydney Samuel Hough | 28 February 1895 |
| NLB/67/561 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Hugh Frank] Newall, FRS | 22 January 1925 |
| NLB/67/121 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Hugh Frank] Newall, FRS | 28 October 1924 |
| NLB/67/642 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to the Editors of the 'Observatory'; Royal Observatory, Greenwich | 5 February 1925 |
| NLB/67/482 | Copy letter from James Hopwood Jeans, Secretary of the Royal Society; to Professor [Hugh Frank] Newall, FRS | 7 January 1925 |
| NLB/14/599 | Copy letter from Robert William Frederick Harrison, to Professor George Howard Darwin, Fellow of the Royal Society | 7 April 1897 |
| NLB/15/624 | Copy letter from Robert William Frederick Harrison, to Professor Andrew Russell Forsyth, Fellow of the Royal Society | 5 November 1897 |
| RR/13/195 | Referee's report by George Howard Darwin, on a paper 'On the application of harmonic analysis to the dynamical theory of the tides. — Part I. On laplace’s "oscillations of the first species” and the dynamics of ocean currents' by Sydney Samuel Hough | 24 February 1897 |