Gradenigo's tuning fork, with amplitude index
1901-1930
1901-1930
1901-1930
1900-1943
1880-1895
1871-1900
1880
1968
1851-1950
1851-1900
1880-1920
1975-1981
1850-1950
1901-1930
1801-1900
1820-1890
1850-1900
1885
1880
1880
1900-1980
1801-1850
1920
1960-1969
1880-1895
1874-1900
1869-1874
1870
1918
1880
1926-1954
1901-1930
1851-1900
1880-1930
1880