A VICTORIAN OXIDISED AND LACQUERED BRASS FORTIN-TYPE LABORATORY MERCURY STICK BAROMETER Baird and Tatlock, London, late 19th century The instrument with slender cylindrical case with the upper section fitted with a glass sleeve enclosing silvered scale incorporating vertical slot to reveal the tube and sliding silvered Vernier slide reading against silvered scale calibrated in barometric inches to the right and millibars to the left, the lower margin signed BAIRD & TATLOCK, LONDON and numbered 2013, the shaft with Vernier adjustment disc to right over applied mercury tube thermometer with bulb within protective housing and Fahrenheit scale, the base with cylindrical glass chamber enclosing mercury and incorporating inverted ivory level pointer to interior clamped between horizontal plates over cylindrical cistern and adjustment screw to base, mounted via a brass ring to top and base collar-bracket with triple securing screws onto a rectangular moulded walnut panel incorporating curved top and base, fitted into a rectangular cabinet with shaped-outline crest over moulded cornice and channel-moulded uprights flanking the rectangular glazed door fitted with ivorine button inscribed BAIRD & TATLOCK, LONDON to lower rail, with further glass panels to sides and on moulded base. The instrument 109cm (43ins) high; the cabinet 132cm (52ins) high, 27cm (10.5ins) wide, 17cm (6.5ins) deep. Provenance: The Selwyn Demmy Collection. The firm of Baird and Tatlock are recorded in Banfield, Edwin BAROMETER MAKERS AND RETAILERS 1660-1900 as a partnership between Hugh Harper Baird and John Tatlock formed circa 1881 specialising as Laboratory furnishers, chemical, mathematical and philosophical instrument makers. They supplied the Admiralty, the War Office, the India Office and the Crown Agents for the Colonies and operated from several addresses in Glasgow and Edinburgh as well as from 14 Cross Street Hatton Garden from 1889. The business became a Limited Company in 1897 and continued to trade from the same London address until 1935. The current lot is made to the principles laid down by Nicholas Fortin (1750-1831) and incorporates a glazed cistern so that the level can be calibrated via the adjustment screw to the base against an inverted conical ivory cone in the cistern in order to obtain consistency in the readings. This particular type of barometer provides an accurate reading hence was generally adopted for laboratory use throughout the 19th and early 20th centuries. Condition Report: Instrument is filled with mercury and provides a good reading with no apparent airlocks. The silvering to the scales is in fine condition with minimal discolouration/mellowing and the Vernier slide is operational. The brass case is in good original condition retaining its original finishes with only slight spotting a wear to the lacquer in places. The cabinet is in good original condition with only minor age related bumps, scuffs and minor blemishes. Condition Report Disclaimer