A very good aneroid pocket barometer altimeter No B.19029 by Short & Mason for Army & Navy Cooperative Stores Ltd, London c1930

Pocket barometer having 1¾” silvered and die struck dial, outer bezel-activated altitude ring calibrated in feet with a range from 0-8,000ft divided down to 100ft, inner barometric scale calibrated in inches of mercury with a range from 23” – 31” and divided down to 1/20”. The upper part marked “Compensated for Temperature” with serial “No. B.19029,” the lower part signed by the maker, “Short & Mason, London, made for A & N.C.S. Ltd, Westminster.” Blued steel pointer under bevelled glass.

The 2nd quality movement of conventional pattern, driven from a single 1” capsule tensioned on a C spring, the chassis struck with “S&M” logogram, all contained within a semi-barrel form case with ribbed finisher and engine turned bezel. The verso with calibration port, case extension and suspension ring.

Presented with its correct clamshell burgundy leather over timber, blue velvet lined case, snap closure on a button release.

Condition: Fully serviced, conserved, and calibrated under laboratory conditions, the movement working well providing quite respectable accuracy over the standard barometric range, see performance chart.

The dial clean and damage free, very slight ageing. The glass with one very small shale to underside of bevel, otherwise damage-free. The bezel moving with correct resistance. The case retaining virtually all its original lacquer, being bright and vibrant. The leather case the subject of some conservation, structurally sound with good polish, some marks, impressions and losses, the catch working perfectly.

Comments: This is not a particularly rare type, though it is very unusual in this condition. Of particular interest is the chassis struck with S&M logogram, quite unusual – most were not so marked. The “B” quality movement is compensated for temperature and has the altitude scale in 100ft divisions – see the image taken from the Short & Mason Tycos catalogue of 1911 (1st quality instruments were divided to 50ft and were in higher quality travel cases, 3rd quality “C” instruments were not compensated).

This makes a very attractive collector’s or connoisseur’s piece, now really hard to find for the scarcity and condition.