A RARE SUBMARINE ANEROID 'SNORTING BAROMETER'ATTRIBUTED TO KELVIN HUGHES LTD, LONDON, CIRCA 1961The 8 inch circular dial calibrated white on black with barometric inches to circumference divided into tenths the centre with infillprising three diminishing sectors finished in green, yellow and black corresponding to zones of decreasing pressure and inscribed R /PO/ 7605 set behind plexiglass cover secured within a square grey painted metal surround with twin lamp covers, brightness adjtment knob and inscribed WHEN PRESSURE TESYING APARTMENT, THIS BAROMETER MT BE REMOVED FOR, THE DURATION OF THE TEST to lower margin and with additional white label inscribed ANEROID, BAROMETER VIA, MISC.J.B. 16 to lower right hand corner, the left hand side of the case also with silvered plate inscribed ANEROID BAROMETER, ADMIRALTY PATTERN No 750, MANUFACTURERS TYPE No KKBA 0501, SERIAL No. GI 315/6i, KELVIN & HUGHES LTD, BASINGSTOKE, YEAR OF MANUFACTURE 1961.25.5cm (10.125ins) square, 8cm (3.125ins) deep.Provenance: The exhibition collection of Barometer World Meum, Merton, Devon.The firm of Kelvin and Hughes Limited was formed in 1947 with the merger of Henry Hughes and Son Limited of London with Kelvin, Bottomley and Baird Limited of Glasgow.The current lot would have been one of two such instruments installed into a diesel-powered submarine, one in the engine room, the other in the control room. The purpose of these barometers is to monitor the internal pressure of the submarine whilst it is submerged with the engines running. In this configuration the engines will be 'snorting' air via an induction mask passing up to the surface. This mast is fitted with a ball-valve to stop the engine taking on water in the event of a being submerged by a wave. Whilst the ball valve is shut the engines will cae the pressure to drop within the submarine which, if allowed to drop too much, could have serio consequences on the crew as well as the operation of the engines. The sectors marked in the centre of the instrument indicate when there is likely to be a problem, so that themand can take appropriate action by either adjting the height of the induction tube, course of the submarine or, if in the red zone, shut down the engines.