'Velocity modulated receiving tubes. Theoretical notebook' (pages torn from a ledger-type foolscap notebook). Notes begin 'The following are the results of calculations carried out between December 1939 and June 1940' and are dated 10.6.40. Later notes are headed 'Theory of velocity modulated oscillators'.

Correspondence etc. regarding Memorandum by Strachey, published in Wireless Engineer, May 1940, correcting a previous letter on velocity modulated beams by R. Kompfner. Kompfner corrected his article and also corresponded with Strachey. A copy of Strachey's 'Memorandum' is enclosed.

Miscellaneous correspondence and memoranda on velocity modulation. Includes a copy of a letter from Strachey to P.B. Moon regarding velocity modulation and klystron, 1942.

Bundles of notes, almost all with numbered pages, n.d. but probably begun in 1940. 'Dynamic Similarity in Large Gaps', 3 pages. 'Reflecting Fields with Space Charge', 15 pages. 'D.C. Transit Time in a Reflecting Field', 7 pages. 'Theorem in Reflecting Fields', 4 pages. 'Conditions for ... reflexion in the absence of space charge', 2…

Three bundles of notes, graphs and calculations: 'H.F. Slope of Infinite plane diode'. 'Calculation of field in cylindrically symmetrical system'. 'Fremlin's Integral' (J.H. Fremlin was a colleague and collaborator of Strachey's at Standard Telephone & Cables).

Three bundles of untitled notes with numbered pages, and miscellaneous loose pages. n.d., c.1942. Includes a copy of the letter to P.J. Daniell arranging for Strachey and Wallis to visit him to discuss velocity modulation, 1942.

Folder 'Miscellaneous Maths'. Three bundles of notes on numbered pages, on Fourier coefficients. Notes on Hahn functions. Notes on Elliptic functions. Shorter notes on Laplace transforms, etc.

Bundles of notes, 'Problems'. Manuscript notes on calculation of the date of Easter, signed H. Spencer Jones 27 February 1943. Brief correspondence regarding work at Ilminster, 1942.

Bundle of notes and diagrams 'Counters for D.A.', n.d. Extensive bundle of notes 'Shell Velocity Tables prepared for Standard Telephone & Cables, July 1945'. Miscellaneous notes on circuitry and switching, n.d. Folder includes letter from P.J. Wallis, 1944.

An extended series of notes, in pencil, in a sequence of 4 bundles: 'Bessel Functions', pages 1-30; 'F of 3rd Kind', pages 31-49; '2nd Type', pages 50-68; 'Fourier-Bessel Series', pages 69-77. Shorter notes on 'Bessel Functions'.

Two bundles of notes, in pencil, in sequence,pages 1-16 and pages 17-34. Bundles of notes on τ functions. Miscellaneous notes on 'Contour or Complex Integration'. One-page note 'Peano', dated on verso 1945. Other manuscript and duplicated material (not by Strachey), 1945.

Autograph manuscript of an extended report on 'The Theory and Design of Velocity-Modulated Oscillators'. The manuscript is dated February 1945 (an earlier title-page is dated July 1944) and has a space for the Value Laboratory Report number to be inserted. Folder includes summary, contents, text, references, tables, and indexes. Included in the folder is a bundle of early notes and drafts for the report, written on the back of an adaptation by Strachey of 'The Crooked…