Abstract :
This paper gives an account of the discovery of the cavity magnetron in the University of Birmingham by the authors, and of subsequent developments in that laboratory including the discovery by Sayers of what is now known as strapping. From October, 1939, to August, 1941, the work was carried out by the authors who, from June, 1940, received much technical help from S. M. Duke. Sayers began work on the magnetron in the summer of 1941 and his ideas on modes led almost immediately to the introduction of straps. Sayers´s detailed work will later be the subject of a separate paper.
