A WILLIAM IV MAHOGANY MERCURY WHEEL BAROMETERUNSIGNED, CIRCA 1830The 8 inch circular register engraved withpass rose to centre within concentric scale calibrated in barometric inches and with the ual observations within cast brass glazed bezel, the flame figured mahogany case with hygrometer to the swan neck pediment over bowfronted Fahrenheit scale spirit tube thermometer to the tapered upright and recording hand setting square beneath dial, the square base inset with glazed spirit level over cavetto moulded underside.100cm (39.5ins) high excluding finial, 25cm (10ins) wide.Provenance: The retail stock of Barometer World Meum, Merton Devon.