Pocket Barometer Retailed by Thomas Armstrong No 263 c.1885

A good quality cased lacquered brass pocket barometer altimeter retailed by Thomas Armstrong & Brother No 263, c.1885. Pocket barometer having 1¾” die struck and silvered dial, the outer altitude ring marked “Higher, Lower, + or – 1,000” with twin subscales divided in 100ft and 50ft increments the range 0 – 7,000ft, the inner scale divided to inches of mercury with a range 23” – 31”. Fine blued steel pointer, the upper dial with standard meteorological terms “Stormy,” “Rain,” “Change,” “Fair,” “Very Dry,” further annotated “Compensated.” The lower portion signed by the maker “Thomas Armstrong & Brother, Manchester & Liverpool” with serial no. “263.” Rotating bezel carrying the altitude ring, bevelled glass. Conventional 1” capsule driven movement with bimetallic compensation, unusual cast chassis with foundry mark “J.P. No 36.” Barrel form case, the verso with compensation port and screw. Pillar and suspension ring. Contained within its original leather covered cream silk and very fine dark blue velvet lined presentation case. Snap closure on a button release. Conditions: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. This pocket barometer remains in absolutely original condition. The lacquered finish slightly marked with some minor wear, dial and glass excellent, the presentation case leather outer with some marks staining and wear, the lid silk aged with some staining, the velvet to lower case excellent. Comments: A quality instrument, working well and in good and very original condition, the presentation case adding extra interest. The movement unsigned, but probably by Negretti & Zambra. The cast iron chassis marked “J.P. No 36” found on another pocket barometer on this site, that one retailed by Chadburn. A very collectable piece and a thoughtful gift.