This Section comprises letters received in Bullard's correspondence folders or as losse papers. Other correspondence kept by Bullard with his research, committee or publications papers has been left in place in the approprate Sections.

The remaining letters are sporadic in incidence. Though there are a few from earlier periods, there is very little from the National Physical Laboratory and the majority date from the later part of Bullard's career. Several contain historical reminiscences, or Bullard's views on research, its organisation and personnel.