Voltmeter, metal face set in wooden casing
1916
Sphere-gap kilovoltmeter (incomplete)
1919-1940
voltmeter no. 11334 - 200-250v.
1900
Kelvin Station type Voltmeter, early 20th Century
1900-1920
Hartmann and Braun voltmeter no.10222 scaled 0-650V
1890
Multi-cell voltmeter
1900-1920