Bristol Aeroplane Company Test Gauge
The brass scale indicates it was for use on the Hercules, Perseus and Centaurus engines. The instrument is stamped FB101192/2MM and has BAC and a broad arrow crudely engraved below. The Perseus engine was used on the Lysander aircraft, while the Centaurus entered service in 1942 on the Warwick, Tempest and Fury. The Hercules was fitted to the Bristol Freighter which entered service in 1945. The scale indicates 0 - 30 and appears to be some sort of pressure testing instrument, circa 1945. 45 cm (17.5").