This sub-series consists of 3 files relating to Edward Appleton’s research into sunspots and solar cycle, dating from the 1930s to 1964. Appleton published several papers on sunspots, and he and his collaborators accumulated much data on sunspot cycles, comparative results at various stations, etc., which can be found in Coll-37/F. The files in this sub-series contain Appleton’s own notes and drafts, and a sample of some of the data.