The material consists of notes, drafts and correspondence. The early material was described by C. S. Gillmor as 'work on pulse characteristics of receivers, and problems of receiving atmospherics'. The later material (from c. 1929) is mainly on the effects of thunderstorms.

Correspondence and data, dated 1942. The material mainly relates to the influence of water vapour density.

The material consists of correspondence and data on seasonal variations, enclosing graphs of Slough observations for 1936, from R. Naismith, dated 1937; and 1 page of notes by L.J. Ingram, annotated by Appleton, no date.

Correspondence and data by Edward Appleton and C.P. Bell, dated June 1958-December 1958. The material is mainly on γ values modified to remove seasonal variation, and includes graphs and tables by Bell and AppletonThe material is mainly on γ values modified to remove seasonal variation, and includes graphs and tables by Bell and Appleton.

Correspondence and data by Edward Appleton and William Farvis, October 1957-December 1957. The material includes Edward Appleton's letter discussing arrangements for C.P. Bell to do 'a certain amount of computational work', and explaining research projects, and some notes by W.E.J. Farvis.

Correspondence and data from R. Naismith to Edward Appleton, dated 1934.

Correspondence and data from R. Naismith to Edward Appleton, dated 1948.

Correspondence and data from W.R. Piggott to Edward Appleton, dated 1939. The material includes an extensive manuscript report on experiments.

Correspondence and data on F₂ layer from W.R. Piggott to Edward Appleton, dated 1947.

Correspondence and data with Edward Appleton, dated January 1959-March 1959.