An exceptional early aneroid pocket barometer altimeter and numbered Singer’s Patent compass No 22803 retailed by Cox, Devonport & Plymouth c1866

Pocket barometer having 1¾” silvered and die struck dial, the outer bezel operated altitude ring calibrated in feet with a range from 0 – 10,000ft divided down to 100ft. The barometric scale calibrated in inches of mercury with a range from 21” – 31” divided down to 1/20th. The  upper part marked “Cox”, the lower with retail location, further marked “Compensated.” Blued steel pointer, bevelled glass. Pendant and bow, with calibration port to verso.

The detachable, push fit compass with full width mother of pearl dry card of Singer’s Patent pattern, displaying cardinals and inter-cardinals, marked “Singer’s Patent” along with serial no. “22803,” side mounted lever pattern lock. The instruments contained within autonomous though closely fitting drum form cases, engine turned trim and bezel rings.

Presented in its original two tier brown leather over timber cream silk and green velvet lined case, snap closures on button releases.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement working very well with maximum observed error of 0.2” across the entire range 21 – 31 inches Hg.

The barometer dial with light barely noticeable marks, bezel and altimetric scale rotating with correct friction. The compass an interference fit with the verso of the barometer case, swinging freely and easily finding north, the lock working properly. Both instruments retaining much original lacquered finish.

The leather travel case structurally sound with good external lustre, the fabric interior with ageing and some staining. Both button releases locking and releasing properly.

Comments: A very hard to find instrument and especially in this condition, numbered Singer’s Patent compasses considered especially rare. With a higher range, to 10,000ft or 21” Hg, this piece demonstrates much better than average accuracy and is a testament to the original quality of the instrument.

The combination of original condition, quality and rarity set this aside as very desirable.