A very unusual Exhibition quality open dial aneroid barometer with thermometer no 221 by Breguet c1863

Aneroid barometer having open silvered and engraved Italian language dial with standard meteorological terms, the barometric scale calibrated in centimetres of mercury with a range from 72cm – 80cm, divided down to 1/20cm.

Marked “No. 221” at 9 o’clock and with the Breguet logogram at 3 o’clockclock. The lower part with semi circular thermometer, the register calibrated in centigrade with a range from 10° to 50° divided down to 1°, marked underneath “Thermometro Centigrade” and “Barometro Anéroïdo.” Blued steel pointer, gilt index, heavy flat glass with finely polished bevel.

The Exhibition quality rack and pinion movement driven from a nickel silver alloy 3” diameter soldered capsule tensioned on a C spring incorporating a transverse stiffening bar and static mass, the connection between primary lever and spindle executed as a finely set chain. High polished brass and steel components with precision mirror finish.

The whole contained within a drum form case with flared mouth, pendant and bow. Calibration port to verso.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement in generally fine condition and working well with smooth and sensitive transition across the indicated range.

The glass with some chips at one point at extreme edge, the case with traces of original finish, minor dent to verso and back edge, the dial aged but clear and legible.

Comments: In January 1863, Maison Breguet took over production of Lucien Vidie’s aneroid barometers for the European market, initially utilising Vidie’s “Bielle Oblique” patent of 1858. This instrument represents an interesting enhancement of that patent, replacing the steering lever with a fine chain, the intention being the reduction of static mechanical friction at the interface of moving parts.

Clearly this is not a mainstream production piece. Examples by this maker are seldom seen, and the Exhibition quality barometer represents the very finest making from a premier watch and clock specialist.

This instrument was likely prepared to special order for scientific or meteorological use, or possibly as a demonstration piece for the Italian market.

An important commentary on the best of French making and innovation from the mid 19th century.

A similar aged, more traditional “Belle Oblique” Breguet movement is here: Breguet’s Barometer No 264.