Hardback notebook, inscribed on cover 'Daily N .P. L. Transmissions 100λ', 1928-1930

Hardback notebook, inscribed on cover 'Daily N .P. L. Transmissions 100λ' and inside (not in Appleton's hand) 'N.P.L. Transmissions on 100 Metres Daily, Commencing November 18 1929 from 12 to 12.30 p.m.' The notebook contains a daily log of experiments and notes, all in Appleton's hand, for 33 days (to 20 December 1929). It also contains observations for 16 January 1930, and earlier notes from 1928 and 1929, and a narrative summarising results. Inside the rear cover is a log of the experiments numbered 1-35 (not all completed).