POST OFFICE BOX, WHEATSTONE BRIDGE

Fitted in elegantly polished wooden case with two ratio dial of 10,100 and 1000 ohms each and a resistance arm of four dials, each of ten coils of 1, 10, 100 and 1000 ohms, giving total resistance of 11,110 ohms, with 4 mm socket terminals for battery, galvanometer and unknown resistance, highly stable resistance area used. Accuracy +0.1%.