Zenith X-ray tube and shield
1901-1913
1901-1913
1986
1999
1892-1943
around 1922
circa 1945-1950
1980
1978-1980
1930-1950
1900-1990
1933
1900-1990
1965-1975
1851-1950
1900-1990
1900-1990
1982-1987
1915
1920-1955
1969
1900-1990
1962
1900-1990
1961-1975 (estimated)
1900-1990
1900-1990
1991
1985-2000
21 January 1934
1900-1990
1972
1900-1990
1963-1964
2003
1955-09-13
1970-1980
1957-07-18
1920-1935
1979-1986
circa 1920
1900-1990
1974-1984
1950-1970
1900-1990
1975-1984
1701-1800