Letter, 4 August 1868
Letter, 20 August 1868
Letter, 24 October 1869
Letter, 6 November 1869
Letter, 14 November 1869
Letter, 28 November 1869
Letter, 10 October 1869
Letter, 13 September 1869
Notebooks of chemical lectures, 1869-1870
Lecture and laboratory notebooks, 1869-1870