Correspondence from C. Størmer to Edward Appleton, dated 1935 and 1947.

Correspondence from Cable and Wireless to Edward Appleton; correspondence from A. Copisarow to Appleton, including draft report; and correspondence from N. Corry to Appleton. All material is dated 1946.

The material consists of correspondence from D. Whitteridge to Edward Appleton, dated 1956. It relates to natural temperature regulation.

Correspondence from D.F. Martyn to Edward Appleton, dated 1948-1949. The material mainly relates to U.R.S.I. [Union Radio-Scientifique International] reports.

Correspondence from D.H. McIntosh to Edward Appleton, dated 1953-1959.

Correspondence from D.H. Menzel Edward Appleton, dated 1947 and from R. Naismith to Edward Appleton, dated 1946.

The material consists of correspondence from D.K. Bailey to Edward Appleton containing comments on Appleton's 1944 papers on morphology of the F2 layer and correspondence from R. Bailey to Appleton, relating to Falkland Islands observations, dated 1948.

Correspondence from D.R. Hartree to Edward Appleton. The material consists of 2 letters from 1930, 3 from 1932, 1 from 1934 and 1 from 1936 and they relate to various research problems and results.

Correspondence from D.W. Heightman to Edward Appleton. Heightman was a radio broadcaster (G6DH) who observed the 'hissing phenomenon' in 1936 and corresponded with Appleton, and with Wireless World, on the subject. In 1945, further correspondence ensued and Heightman's letter of 6 July 1945 encloses observations noted 1936-39. Appleton acknowledged Heightman's early observations in some of his later writings on solar noise.

Correspondence from E. Eastwood to Edward Appleton, dated 1945-1946. The material includes data and observations at various R.A.F. stations for 1942 and 1946