Improved Callendar and Griffiths Resistance Bridge, 1850-1900
1850-1900
1850-1900
1850-1900
1905 (invented); 1907-1920
1887
1895-1910
1886-1930
1886-1930
1902-1930
1886-1930
1886-1930
1887
1886-1930
1905-1906
1905
1894
1910
1886-1930
1914
1904
1897
1900-1928
1886-1930
circa 1910