
'Cat's whisker' Crystal Radio
1920-1925
1920-1925
1839 (original); circa 1988 (replica)
1923
1952-3
1920-1925
1925
1928
1921
1934
1927
1924
1927
1924
1927
1925
1920-1929
1923
1924-1927
1925
1928
1924
1920
1928
1922
1955; 1830
circa 1920
1927
1921-1926
1926
circa 1920
1922-1923
1922-1923
1922-1923
1922-1923
1921
1920
1920-1928
1928
2000-100 BCE
1920-1928
before 1928
1923
1920
1926
1926-1928
1927
1801-1892 (prepared); 1946 (element replaced)
circa 1920
1920
1925