Several detectors, at the rear, from left to right:
Made by G.E.C. London, Witton & Manchester England.
Silvertown 1916, table top detector galvanometer .
Table top differential detector galvanometer marked: “P.R.E.W. 1916”.
Detector made by Henley London.
Front row, from left to right:
Intensity and quantity detector (I & Q) made by Edison & Swan, No.26400 1919.
G.P.O. detector (I &Q) with switch to change shunt coil from Full to 1/5 Shunt.
Unmarked I & Q detector galvanometer.