Letter from R. W. Ward, the General Post Office, to James Mackenzie Davidson Encloses a license to conduct experiments in wireless telegraphy [enclosed - see MS/1/929/222a]. Notes that, with reference to clause 5 (2) of the license, the Postmaster General has found it desireable to lay down a general rule that stations should have a distinctive call-signal, and each station when signalling begin with the call signal of the station with which it wishes to communicate. 1 January 1914