A fine aneroid pocket barometer altimeter constructed by Short & Mason No. D.19236 for Ross, London c1935

Aneroid pocket barometer having 1¾” silvered and die struck dial, drilled at three points to the circumference for direct fixing to the chassis via stand offs. Outer bezel set altitude scale calibrated in feet with a range from 0-8,000ft divided to 50ft, inner barometric scale calibrated in inches of mercury with a range from 23” – 31” divided to 1/10”, the upper part marked “Compensated for Temperature” with serial “No D.19236,” the lower signed by the retailer “Ross, London” and “Made in Gt Britain. Blued steel pointer, bevelled glass.

The good quality lacquered brass frosted movement driven from a single 1¼” nickel alloy capsule tensioned on a C spring, all raised on a circular chassis with three dial standoffs, the chassis carrying the Short & Mason “S&M” logogram. The whole maintained within a semi-barrel form case with pendant and bow, engine turned finisher to bezel, calibration port to verso. Original retailers label attached bearing Short & Mason’s “SM London” arrow logogram and “Tycos” brand.

Presented in its original burgundy leather over timber, green velvet and silk lined case, the retailer’s Royal Warrant and trading particulars in gold block to inner lid silk. Snap closure on a button release. Marked with initials “G.E.S.W.” in gold block to lid.

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

The dial about fine. The brass case retaining virtually all its original lacquered finish. The leather travel case crisp overall with good colour, the internal fabric retaining much of its original vibrancy.

Comments: This instrument is unusual for two reasons. First, it is a documented example of Ross retailing a Short & Mason product. Second, the method by which the movement is constructed as integral with the dial is very unusual – only one or possibly two examples of this means of construction have been noted, the normal method of construction being to attach the movement to the inner case back by means of screws and threaded ferrules soldered into the inner back. This arrangement, where the dial and movement are constructed as a single assembly, negates the requirement to solder ferrules into the back of the case with attendant issues of correct alignment. It does however involve the production of standoffs and the resultant operations to precisely align the dial and movement. This means of construction would appear to have been in production for only a very short period of time, perhaps no more than a few months, and costs would probably have been higher with negligible benefit either in function or assembly.

This is a very fine instrument, its overall condition setting it well apart from most. Very much a collector’s piece.