Unusual Expedition or Chart Table Aneroid Barometer by Short & Mason c.1890

An unusual expedition or chart table type lacquered brass aneroid barometer with short altimetric scale by Short & Mason circa 1918. Aneroid barometer having 4¼" silvered and die struck dial, the outer altitude scale calibrated in feet with a range from 0 – 3,000ft divided down to 10ft, the inner barometric scale calibrated in inches of mercury with a range from 28" – 31" divided down to 1/100th". Fine blued steel pointer, heavy bevelled glass. Bezel operated index. Conventional Vidie pattern movement driven from a single 1¾" nickel alloy capsule tensioned on a C spring. All contained in a substantial brass drum form case. The suspension ring and pendant removed. Calibration port to verso. Presented in a well executed finger jointed mahogany, plum velvet-lined case. Snap closure on button release. Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement working exceptionally well with a max error of .03” across the range. The dial clean and essentially damage free, the bezel and index moving with precision. The timber case with shrinkage cracks top and bottom, the top one wax filled. Structurally sound with good colour, the velvet lining somewhat faded to lid. Comments: This is a very interesting piece and it is unclear precisely for what discipline it was intended. The barometric scale would indicate meteorology, the large and open scale affording much better than average resolution. The transport case is almost certainly an original manufacturers product. It is very unusual and of first class quality. See a very similar, albeit smaller, example also listed on our site.