Lord Kelvin's 'ironclad' marine galvanometer, 1865-1866
1865-1866
1865-1866
1855-1860
1858
1858
1843-1897
1858
1830-1870
1854
1864-1886
1881-1926
1920-1930
1959-1961
1910-1920
1943-1970
1890-1930
1900
1955
1910
1901-1908
1890-1891
1906
1935
1920
1963
1890
1859
1880-1920
1920-1955
1888
1850-1924
1852-1870
1926
1926
1878-1900
circa 1902-1925
1908
1858
1937
1903
1906
1960
circa 1910