| RefNo | Title | Date |
| NLB/2/449 | Copy letter from Herbert Rix, to Dr William Marcet [Fellow of the Royal Society] | 4 July 1888 |
| NLB/4/158 | Copy letter from Herbert Rix, to Dr William Marcet | 26 February 1890 |
| NLB/4/192 | Copy letter from Herbert Rix, to Dr William Marcet | 7 March 1890 |
| NLB/4/246 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 24 March 1890 |
| NLB/2/931 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 2 January 1889 |
| NLB/3/298 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 2 May 1889 |
| NLB/3/865 | Copy letter from Herbert Rix, to Messrs West, Newman & Company | 29 October 1889 |
| NLB/3/425 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 7 June 1889 |
| NLB/3/600 | Copy letter from an unknown correspondent, to Messrs West, Newman & Company, 54 Hatton Garden | 22 July 1889 |
| NLB/3/741 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 27 September 1889 |
| NLB/3/703 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society, Malagny, Versoix, Geneva | 20 September 1889 |
| NLB/6/507 | Copy letter from an unknown correspondent, to Messrs Clay & Sons, Ave Maria Lane, E.C. | 26 May 1892 |
| NLB/6/503 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 26 May 1892 |
| NLB/6/810 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 19 July 1892 |
| NLB/11/393 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 21 June 1895 |
| NLB/11/284 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 26 May 1895 |
| NLB/12/80 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 6 December 1895 |
| NLB/14/142 | Copy letter from Robert William Frederick Harrison, to Dr William Marcet, Fellow of the Royal Society | 11 January 1897 |
| NLB/16/741 | Copy letter from Robert William Frederick Harrison, to [William] Marcet, Flowermead, Princes Road, Wimbledon Park | [1 June 1898] |
| NLB/17/69 | Copy letter from Robert William Frederick Harrison, to Dr William Marcet, Fellow of the Royal Society | 13 July 1898 |
| NLB/20/260 | Copy letter from Theodore E James, to Messrs Harrison & Sons | 8 March 1900 |
| RR/3/190 | Referee's report by Lyon Playfair, on a paper 'On the action of bile upon fats; with additional observations on excretine' by William Marcet | 13 October 1858 |
| RR/7/110 | Letter from George Gabriel Stokes, on a paper 'An experimental inquiry into the constitution of blood and the nutrition of muscular tissue' by William Marcet to the author | 12 December 1871 |
| RR/10/286 | Referee's report by John Gray McKendrick, on a paper 'A chemical inquiry into the phenomena of human respiration' by William Marcet | 25 June 1889 |
| RR/5/139 | Referee's report by Henry Bence Jones, on a paper 'On a colloid acid, a normal constituent of human urine' by William Marcet | 7 July 1864 |
| EC/1857/08 | Marcet, William: certificate of election to the Royal Society | |
| NLB/3/402 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 1 June 1889 |
| NLB/3/623 | Copy letter from Herbert Rix, to Dr [William] Marcet, Fellow of the Royal Society, Malagny, Versoix, Genève | 25 July 1889 |
| NLB/3/885 | Copy letter from Herbert Rix, to Dr William Marcet, Fellow of the Royal Society | 5 November 1889 |
| NLB/14/487 | Copy letter from Michael Foster, to Dr William Marcet, [Fellow of the Royal Society] | 18 March 1897 |
| RR/10/285 | Referee's report by Edward Frankland, on a paper 'A chemical inquiry into the phenomena of human respiration' by William Marcet | 10 June 1889 |
| RR/5/138 | Referee's report by Thomas Graham, on a paper 'On a colloid acid, a normal constituent of human urine' by William Marcet | 30 June 1864 |
| RR/2/147 | Referee's report by Alfred Swaine Taylor, on a paper 'An account of the organic chemical constituents or immediate principles the excrements of man and animals in the healthy state' by William Marcet | 24 June 1854 |
| PT/49/4 | Paper, 'An account of the organic chemical constituents or immediate principles of the excrements of man and animals in the healthy state' by W [William] Marcet | [1854] |
| RR/4/159 | Referee's report by William Sharpey, on a paper 'On the action of bile upon fats; with additional observations on excretine' by William Marcet | 25 January 1859 |
| RR/2/148 | Referee's report by George Owen Rees, on a paper 'An account of the organic chemical constituents or immediate principles the excrements of man and animals in the healthy state' by William Marcet | 6 July 1854 |
| RR/3/186 | Referee's report by Lyon Playfair, on a paper 'On the immediate principles of human excrements in the healthy state' by William Marcet | 6 April 1857 |
| RR/3/189 | Referee's report by Henry Bence Jones, on a paper 'On the action of bile upon fats; with additional observations on excretine' by William Marcet | 31 July 1858 |
| AP/41/5 | Unpublished paper, 'On the action of bile upon fats with additional observations on excretine' by W [William] Marcet | 1858 |
| RR/7/108 | Referee's report by William Odling, on a paper 'An experimental inquiry into the constitution of blood and the nutrition of muscular tissue' by William Marcet | 2 October 1871 |
| RR/7/109 | Referee's report by John Scott Burdon-Sanderson, on a paper 'An experimental inquiry into the constitution of blood and the nutrition of muscular tissue' by William Marcet | 20 October 1871 |
| AP/53/5 | Unpublished paper, 'An experimental inquiry into the constitution of blood and the nutrition of muscular tissue' by William Marcet | 1871 |
| PP/9/2 | Paper, 'An instrument for the speedy volumetric determination of carbonic acid' by William Marcet | 1886 |
| PP/9/2/2 | Diagram, 'Dr Marcet's instrument for the speedy volumetric determination of carbonic acid' by James P Maginnis | 1886 |
| PP/18/3 | Paper, 'Researches on the absorption of oxygen and formation of carbonic acid in ordinary human respiration, and in the respiration of air containing an excess of carbonic acid' by William Marcet | 1891 |
| PP/20/18 | Paper, 'Contribution to the history of the interchange of pulmonary gases in the respiration of man' by William Marcet | 1892 |
| PP/22/5 | Paper, 'The influence of exercise on the interchange of the respiratory gases' by William Marcet | 1893 |
| RR/3/187 | Letter from Lyon Playfair, on a paper 'On the immediate principles of human excrements in the healthy state' by William Marcet | 18 April 1857 |
| RR/3/188 | Referee's report by John Stenhouse, on a paper 'On the immediate principles of human excrements in the healthy state' by William Marcet | 15 April 1857 |
| PP/9/2/1 | Manuscript, 'An instrument for the speedy volumetric determination of carbonic acid' by William Marcet | 1886 |
| MC/16/218 | Letter from [William] Marcet, Flowermead, Princes Road, Wimbledon Park, to [Herbert] Rix | 26 May 1895 |
| MC/16 | Volume 16 of miscellaneous correspondence regarding business matters, sent to the Royal Society | 1893-1896 |