A RARE WWII ROYAL NAVY ISSUE SUBMARINE COMPARTMENT DOUBLE-RO...

Estimate

£120 - £180

A RARE WWII ROYAL NAVY ISSUE SUBMARINE COMPARTMENT DOUBLE-ROTATION AIR PRESSURE GAUGET. WHEELER, LONDON, CIRCA 1945The long-range mechanism incorporating 3 inch diameter capsule with Wheeler pattern recuperation spring, twin bronze shrouded recoil hairsprings and bimetallic temperature compensation to the primary lever, the 4 inch circular silvered dial inscribed COMPENSATED, No. 7840/45, MARK I, T. WHEELER, Scientific Inst's LTD, LONDON to centre within two concentric scales calibrated in MILLIBARS, 400-700 and 700-1050 divided into two millibar increments, with black finish steel pointer within canted silvered surround set behind a glazed knurled brass bezel configured to allow the dial to be manually rotated, fitted to the cylindrical aluminium alloy case incorporating moulded collar behind the bezel and brass backplate.12cm (4.75ins) diameter overall, 5cm (2ins) deep.Thomas Wheeler is recorded in Banfield, Edwin BAROMETER MAKERS & RETAILERS 1660-1900 as established at 8 Coombs Road, London by 1893. The firm is further recorded in Grace's Guide as working from 217 Goswell Road, London in 1937. The firm of T. Wheeler were awarded many contracts from the M.O.D. during both wars including altimeters for early aircraft use.Mark Jarrold notes (in his description of instrument No. 7343) that such gauges are designed to mostly operate in an environment with a lower-than-normal atmospheric pressure, which would suggest submarine use. Adding that the monitoring of air pressure within a diesel-powered submarine running submerged via snorkel induction was particularly important to check that air was not being drawn from within the boat due to an obstruction within the snorkel. The manual rotation of the dial also facilitates quick calibration of the instrument which was probably often required in the high-vibration environment of a submarine.