Four items of television transmission equipment associated with John Logie Baird, 1928-1938: 1. 30-line mirror drum from Bush Televisor, c1933 2. 14" mirror drum with twenty mirrors and motor, 1936 3. 10" mirror drum with twenty mirrors, 1938 4. Ventriloquist's dummy head, 1928. Transmission equipment associated with John Logie Baird 1928-1938