1. Speculations on the British secret microwave network are in Campbell, D.War Plan UK(London, 1982).
2. Whitakers Red Book of Commerce or Who’s Who in Business, 1914 edn and subsequent editions.
3. Ms note, dated 1910, on brochure,Description of the Two Instruments exhibited at the Manchester Exhibition, 1861, by Reid, Brothers, London(London, 1861), British Library 08709.bb.7 (2).
4. The dates given are those of the annual editions of the Directory, although it is recognised that the information would have been gathered in or revised up to a year before the date of publication.
5. Kempe H.R. ‘Telegraphic History’, a paper read before the Metropolitan Centre of the Institution of Post Office Electrical Engineers, 11 March 1912.