A fine lacquered brass aneroid pocket barometer altimeter by Ross c1890

Larger pocket barometer having 2¾” silvered engine-divided and engraved dial, the barometric scale calibrated in inches of mercury with a range from 26” – 31” and divided down to 1/20th”, standard meteorological terms, the upper part marked “Compensated,” the lower with ”Ross, London.” Fine blued steel pointer, bevelled glass, rotating bezel mounted index. Suspension post and bow, the verso with calibration port.

Well executed movement raised over a cast steel chassis and driven from a single 1¼” nickel silver capsule tensioned on a C spring, brass sub chassis with cock mounting and spindle pivots. All contained in brass drum form case with engine turned bezel, marked “Ross.”

Condition: The subject of a full service, conservation, and calibration under laboratory conditions. The movement working exceptionally well, see performance chart from dynamic pressure test.

The dial clean, crisp and bright with virtually no signs of ageing. The glass original, remaining damage free. The brass case retaining virtually all its original lacquered finish.

Comments: This is an unusual pattern, the inside of the case roughly engraved “Ross” strongly suggesting that this instrument was made for Ross and not of Ross’s manufacture. Our ongoing research suggests that the maker may have been Casella, but this is not yet confirmed.

Very hard to find in this condition and an interesting piece as a research object in identifying the original manufacturer.