Each volume contains letters to Andrews, the Irish chemist, and is prefaced by a list, compiled by one of Andrews' sons, of the correspondents. The letters are in no particular order and are interspersed with notes, memos and announcements pertaining to Andrews' career. A few letters are earlier than 1842 Oct. The full listing lists the letters: in alphabetical order of correspondent; by subject of the remaining miscellaneous items; in number order as they appear in the bound volumes. They are from many of the leading members of the international scientific community and from those involved in Ulster society and in the affairs of Queen's College (later Queen's University), Belfast.