| Reference number | Title | Date |
| EC/1895/21 | Kohlrausch, Friedrich Wilhelm Georg: certificate of election to the Royal Society | |
| NLB/14/372 | Copy letter from Robert William Frederick Harrison, to Professor Henry Edward Armstrong, Fellow of the Royal Society | 26 February 1897 |
| NLB/14/379 | Copy letter from Henry Edward Armstrong, to Professor [Friedrich Wilhelm Georg] Kohlrausch | 1 March 1897 |
| NLB/14/445 | Copy letter from the Chairman of the International Catalogue Committee, to Herrn Professor Dr Friedrich Wilhelm Georg Kohlrausch, Physikalisch-Technische Reichsanstalt, Charlottenburg, Germany | 13 March 1897 |
| NLB/14/630 | Copy letter from Theodore E James, to Messrs Harrisons & Sons | 12 April 1897 |
| NLB/26/306 | Copy letter from Robert William Frederick Harrison to, Herrn Professor Dr Friedrich Wilhelm Georg Kohlrausch, Foreign Member of the Royal Society | 26 February 1903 |
| NLB/25/722 | Copy letter from Robert William Frederick Harrison, to Friedrich Wilhelm Georg Kohlrausch, Foreign Member of the Royal Society | 15 December 1902 |
| NLB/26/273 | Copy letter from Robert William Frederick Harrison to, Herrn Professor Dr Friedrich Wilhelm Georg Kohlrausch, Foreign Member of the Royal Society | 20 February 1903 |
| NLB/26/47 | Copy letter from Robert William Frederick Harrison to, Herr Professor Dr Friedrich Wilhelm Georg Kohlrausch, Foreign Member of the Royal Society, March-Strasse 25B, Charlottenburg, Germany | 20 January 1903 |
| NLB/26/462 | Copy letter from Robert William Frederick Harrison to, Herr Professor Friedrich Wilhelm Georg Kohlrausch, Foreign Member of the Royal Society | 25 March 1903 |
| NLB/14/645 | Copy letter from Robert William Frederick Harrison, to Herrn Professor Dr Friedrich Wilhelm Georg Kohlrausch, Foreign Member, Royal Society, Physikalisch-Technische Reichsanstalt, March. Str. 25, Charlottenburg, Berlin | 13 April 1897 |