| Reference number | Title | Date |
| EC/1893/17 | Young, Sydney: certificate of election to the Royal Society | |
| NLB/8/846 | Copy letter from Herbert Rix, to Professor Sydney Young, Fellow of the Royal Society, 13 Aberdeen Road, White Ladies Road, Bristol | 9 January 1894 |
| NLB/12/699 | Copy letter from an unknown correspondent, to Messrs Harrison & Sons | 14 April 1896 |
| NLB/28/62 | Copy letter from [Theodore E James], to [Messrs Harrison & Sons] | 4 January 1904 |
| NLB/27/742 | Copy letter from Robert William Frederick Harrison, to Professor Sydney Young, Fellow of the Royal Society, University College, Bristol | 24 November 1903 |
| MC/21/672 | Letter from Sydney Young, 12 Raglan Road, to the Assistant Secretary of the Royal Society | 17 June 1906 |
| NLB/32/62 | Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons | [20 December 1905] |
| NLB/33/99 | Copy letter from Joseph Larmor, to Professor Sydney Young, Fellow of the Royal Society | July 1906 |
| NLB/38/611 | Copy letter from Joseph Larmor, to Professor [Sydney] Young, [Fellow of the Royal Society] | 8 October 1908 |
| NLB/51/468 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society to Professor Sydney Young FRS | 26 March 1915 |
| NLB/53/80 | Copy letter from [Robert William Frederick Harrison]; to unknown correspondent | 5 April 1916 |
| RR/9/390 | Referee's report by Alexander Crum Brown, on a paper 'On the vapour pressures of ether' by William Ramsay and Sydney Young | 4 December 1886 |
| NLB/57/125 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor S [Sydney ] Young, FRS | 28 July 1919 |
| RR/9/387 | Referee's report by George Carey Foster, on two papers 'On evaporation and dissociation. Part II - A study of the thermal properties of alcohol' and 'On evaporation and dissociation. Part I' by William Ramsay and Sydney Young | 29 December 1885 |
| RR/9/389 | Referee's report by James Dewar, on a paper 'On the vapour pressures of ether' by William Ramsay and Sydney Young | 14 August 1886 |
| RR/9/236 | Referee's report by Balfour Stewart, on a paper 'Influence of change of condition from the liquid to the solid state on vapour-pressure' by William Ramsay and Sydney Young | 24 June 1884 |
| RR/9/181 | Referee's report by George Carey Foster, on a paper 'The influence of pressure on the temperature of volatilization of solids' by William Ramsay and Sydney Young | 24 August 1883 |
| RR/9/180 | Referee's report by Balfour Stewart, on a paper 'The influence of pressure on the temperature of volatilization of solids' by William Ramsay and Sydney Young | 12 July 1883 |
| RR/9/237 | Referee's report by George Carey Foster, on a paper 'Influence of change of condition from the liquid to the solid state on vapour-pressure' by William Ramsay and Sydney Young | 1 September 1884 |
| RR/11/199 | Referee's report by George Carey Foster, on a paper 'On some of the properties of water and of steam' by William Ramsay and Sydney Young | 9 January 1892 |
| RR/10/208 | Referee's report by William Grylls Adams, on a paper 'On evaporation and dissociation.—Part VIII. A study of the thermal properties of propyl alcohol' by William Ramsay and Sydney Young | 17 October 1888 |
| NLB/57/574 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society; to Professor S [Sydney] Young, FRS | 8 December 1919 |
| NLB/71/936 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Dr. [Morris William] Travers, FRS, Clifton, Bristol | 10 December 1928 |
| RR/10/209 | Second referee's report by William Grylls Adams, on a paper 'On evaporation and dissociation.—Part VIII. A study of the thermal properties of propyl alcohol' by William Ramsay and Sydney Young | nd [1888] |
| RR/10/77 | Second referee's report by Alexander William Williamson, on a paper 'On evaporation and dissociation. Part V. A study of the thermal properties of methyl-alcohol' by William Ramsay and Sydney Young | 5 May 1887 |
| RR/10/76 | Referee's report by George Francis Fitzgerald, on a paper 'On evaporation and dissociation. Part V. A study of the thermal properties of methyl-alcohol' by William Ramsay and Sydney Young | 26 March 1887 |
| EC/1893/18 | Young, Sydney: certificate of election to the Royal Society | |
| RR/9/388 | Referee's report by William Grylls Adams, on two papers 'On the vapour-densities of alcohol' and 'On the vapour pressures of ammonium chloride' by William Ramsay and Sydney Young | 20 February 1886 |
| RR/11/200 | Referee's report by Arthur William Rucker, on a paper 'On some of the properties of water and of steam' by William Ramsay and Sydney Young | 14 January 1892 |
| RR/10/207 | Referee's report by George Carey Foster, on a paper 'On evaporation and dissociation.—Part VIII. A study of the thermal properties of propyl alcohol' by William Ramsay and Sydney Young | 7 August 1888 |
| PP/10/2 | Paper, 'Preliminary note on the continuity of the liquid and gaseous states of matter' by William Ramsay and Sydney Young | 1886 |
| PP/10/28 | Paper, 'Clausius's formula for the change of state from liquid to gas applied to Messrs. Ramsay and Young's observations on alcohol' by George Francis Fitzgerald | 1887 |
| PP/10/8 | Paper, 'On the thermodynamic properties of substances whose intrinsic equation is a linear function of the pressure and temperature' by George Francis Fitzgerald | 1887 |
| RR/10/79 | Second letter from William Ramsay, to John William Strutt, 3rd Baron Rayleigh, regarding a paper 'On evaporation and dissociation. Part V. A study of the thermal properties of methyl-alcohol' by William Ramsay and Sydney Young | 23 May 1887 |
| RR/10/75 | Referee's report by Alexander William Williamson, on a paper 'On evaporation and dissociation. Part V. A study of the thermal properties of methyl-alcohol' by William Ramsay and Sydney Young | 25 March 1887 |
| RR/10/78 | Letter from William Ramsay, to John William Strutt, 3rd Baron Rayleigh, regarding a paper 'On evaporation and dissociation. Part V. A study of the thermal properties of methyl-alcohol' by William Ramsay and Sydney Young | 14 May 1887 |
| RR/10/80 | Referee's report by Edward Frankland, on a paper 'On evaporation and dissociation. Part V. A study of the thermal properties of methyl-alcohol' by William Ramsay and Sydney Young | 15 June 1887 |
| MC/19/871 | Letter from Sydney Young, University College Bristol, to the Assistant Secretary of the Royal Society | 23 November 1904 |
| MC/19/870 | Letter from Sydney Young, University Chemical Laboratory, Trinity College, Dublin, to the Secretaries of the Royal Society | 5 August 1904 |
| MC/25/271 | Letter from Syndey Young, University Chemical Laboratory, Trinity College, Dublin, to [Robert] Harrison, [Assistant Secretary], The Royal Society | 10 June 1910 |
| MC/21 | Volume 21 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1906 |
| MC/19 | Volume 19 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1904 |
| MC/21/670 | Letter from Sydney Young, University Chemical Laboratory, Trinity College, Dublin, to the Assistant Secretary of the Royal Society | 15 June 1906 |
| MC/21/671 | Letter from Sydney Young, University Chemical Laboratory, Trinity College, Dublin, to the Assistant Secretary of the Royal Society | 16 June 1906 |
| NLB/33/15 | Copy letter from Robert William Frederick Harrison, to Dr Sydney Young, Fellow of the Royal Society, 12 Raglan Road, Dublin | 18 June 1906 |