![](https://coimages.sciencemuseumgroup.org.uk/318/351/large_thumbnail_smg00046860.jpg)
Improved Callendar and Griffiths Resistance Bridge, 1850-1900
1850-1900
1850-1900
1905 (invented); 1907-1920
1850-1900
1887
1895-1910
1886-1930
1886-1930
1902-1930
1886-1930
1886-1930
1887
1905-1906
1894
1910
1905
1886-1930
1886-1930
1897
1914
1904
1900-1928
circa 1910
1886-1930