Maker's Name: 
Cambridge Instrument Co.
63 × 29 × 16 cm

This bridge was used to measure low resistance down to microOhms, particularly that of thick cables. The cablewas strapped between bolts at the top and a large current passed through the cable sample from a battery . Knife edges across the cable form the potential electrodes for the bridge. The current through the cable and voltage at the knife edges can be measured, and the cable resistance calculated for that length between the knife edges.