Comprises:
- B1, Letter to Prinz from GEC Wembley, 16 January 1936, offering him a post in the Valve Development Laboratory;
- B2, Correspondence with Professor M.V. Wilkes re. visit to see EDSAC at Cambridge University; and subsequent notes on EDSAC, October-November 1948;
- B3, Copies of letters re. Ministry of Supply Technical Committee on Servo-Mechanisms, 21 July 1948; and Ferranti and Manchester University Computer, 13, 14, 23 December 1948.