
Original laboratory sample of 'M and B 693', England, 1938
1938
1938
1924-1927
1935-02-22
25 June 1934
25 June 1934
1980
1927-1930
1940
1935-1940
1970-1985
1968
25 June 1934
25 June 1934
1971
1970-1985
1932
1932
1960-1975
1940-1970
1960-1980
1970-1985
circa 1955
1960-1970
1950-1970
1980-1985
1986
1960-1970
1915-1925
circa 1955
1985
1900-1951
1970-1985
1970-1985
1940-1960
1940-1960