A rare oak cased micro-barograph with thermometer Negretti and Zambra, London, early 20th century The mechanism with nine-segment aneroid chamber connected via a lacquered brass armature to an inked pointer for recording the change in barometric pressure on a double-height clockwork-driven rotating paper scale lined drum, the brass baseplate engraved NEGRETTI & ZAMBRA, LONDON and applied with an arched silvered Fahrenheit and centigrade scale mercury tube thermometer, the case with five-panel hinged cover on cavetto moulded skirt base incorporating a drawer containing spare charts over simple squab feet, 49cm (19.25ins) wide. The firm of Negretti & Zambra are recorded in Banfield, Edwin BAROMETER MAKERS AND RETAILERS 1660-1900 as being established in 1850 when a partnership between Enrico Negretti and Joseph Warren Zambra was formed. The firm became one of the most prolific makers of scientific instruments and continued trading well into the 20th century.