The collection is composed of:
- 1833-1841 - mixed documents connected with Professor John Thomson
- 1836-1847 - series of letters between Thomas Chalmers and the Rev. Dr. Muirhead
- 1838 - testimonials in favour of John Thomson and in relation to the Reid Professorship
- 1840 - series of letters from William Chambers (Music publisher) to John Thomson
Also in the collection is a MS document of unknown date and origin.