Antique barometer altimeter by the highly-respected maker John Browning of London. Finely engraved 3½” silvered brass dial, calibrated from 15-31 inches of mercury and 0-18,000 feet. Lower part of dial marked “John Browning, London” and “Patent” and instrument serial “No 57,” together with the formula:

which relates to the compensation factor required for temperature and increase in altitude.

Very fine blued-steel pointer. Heavy bevelled flint glass crystal, very finely ground. Rotating bezel with index point. Beautiful, highest quality, heavy movement executed in bronze and fine-grade steel, finished in the moire fashion to ‘exhibition’ standard. Nickel silver 2¼” capsule. The movement is of the very early Vidi pattern with coil spring, positively dating the instrument to the mid-19th century. The whole contained in heavy, lacquered brass spun case with suspension ring, retaining some original finish. Revolving cover for compensation screw.

Highly sensitive movement in perfect working order. Cleaned and serviced, original, unrestored condition. Very minor flaw to the extreme edge of the crystal; very minor abrasions and wear commensurate with age.

With the range in feet and the formula, this Browning barometer altimeter would have been designed for hot air ballooning.  An extremely rare collector’s item.

Vidi’s original patent for the aneroid barometer expired in 1855, and John Browning started to register patents for various scientific instruments from 1856 onwards. This is a very early instrument, utilising the Vidi coil spring in the movement as opposed to the C-spring that came into wide use in the late 1850s.

Dimensions: 3¾” diameter x 1½” deep

Stock No: BA0283

Price: SOLD