A very unusual and highest quality oxidised brass three function “Surveying Aneroid” no. 12149 by Short & Mason in original case c1890

Surveying Aneroid barometer having 6” stepped dial, wheel operation to silver plated scales: Vernier (outer ring with sector) divided to 10ft, Altitude ring calibrated in feet and divided to 10ft with ascending and descending ranges 0 – 4,000ft and 0 – 3,000ft respectively, and Clamp which maintains the set value for altitude. Barometric scale calibrated in inches of mercury with a range from 27” – 34” divided down to 1/100”. Inner dial marked “Ascent” and “Descent,” “Surveying Aneroid,” and signed by the maker “Short & Mason” with London address, serial no. “12149” and “Compensated.” Very fine blued pointer, heavy bevelled glass.

The exceptional and very unusual movement driven from a single 3⅛” soldered nickel alloy capsule and constructed principally in lacquered brass, having substantial ‘castle’ profile cock, “S&M” logogram, chain guide, and raised on twin turned pillars over a heavy supplementary chassis with spindle and pivots, engraved “Short & Mason, London.”

The whole contained within a very substantial stepped drum form case, the lower part set with “Altitude,” “Vernier” and “Clamp” wheels. The verso with screw fitting and registration pin, calibration port.

Contained within a large leather covered clam-form case, the lower part surviving but in relic condition.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement working exceptionally well, evidence of an earlier chain repair, generally very good condition.

The dial with marks and some staining, the silvered vernier sector, altitude and barometric scales with marks, very light abrasions and some oxidation. The oxidised brass case with much original finish, points of oxidation, abrasion and losses. The control wheels with oxidisation but retaining some original lacquer.

Comments: Probably extremely rare, manufactured to the highest prevailing standard, and certainly produced in very small numbers, any three wheel instrument of this type has to be considered unusual. Marketed as a “surveying” aneroid, given its range this instrument was almost certainly used for mining purposes.

From the point of view of collecting, although this piece must only be described as in fair condition, it is easily good enough and certainly significant enough to add to any collection.