Under this heading are grouped all data, notes and correspondence which were not included in Appleton’s named folders, but were received as loose and disordered papers. Most of them relate to his period at Edinburgh University, when he conducted collaborative research on a number of ionospheric projects simultaneously. His consistent collaborator was A. G. Pritchard (later Turnbull) whose data comprise many different topics; for the period c.1949-54 he also worked closely with A.J. Lyon (see especially Coll-37/C.134-C.156) and c.1957-59 with C.P. Bell (see Coll-37/C.157-C.165) whose correspondence and accompanying data have been left in sequence. Appleton also consulted other colleagues at Edinburgh as well as continuing his collaboration with former colleagues; this correspondence appears in Coll-37/E. See, inter alia, correspondence with A. Aitken, W.J.G. Beynon, W.R. Piggott. It will be seen that there is considerable overlap with other topics (notably 'E Layer' and 'F Layer'); material in this sequence must be regarded as essentially complementary. The only difference is in the provenance, and the absence of a specific folder designation by Appleton. Appleton's own ideas, drafts and notes appear at Coll-37/C.106- C.131, and the remainder of the material (data and correspondence) is presented in approximate chronological order at Coll-37/C.132-C.165.