Aneroid barometer having 4½” china clay finished and printed card dial with standard meteorological terms, the barometric scale calibrated in inches of mercury with a range from 25” – 31” divided to 1/50^th, the centre with decorative star design, the lower part annotated in script “Aneroid Barometer.” Blued steel pointer, skeletal gilt index, bevelled glass.

The finely executed movement driven from a single special pattern 2½” capsule tensioned on a C spring, fine gain and rate adjustments on squares, spherical pattern kinetic mass, all raised over a steel chassis.

The whole contained within a flared drum form case, calibration port to verso, extension post and suspension loop.

Condition: The subject of a complete overhaul, servicing, conservation, and calibration under laboratory conditions. The movement working well, resolving easily acceptable results within the standard barometric range.  Crisp overall, the dial with minor marks, the case retaining traces of original finish, minor damage to rear edge, the verso re-finished.

Comments: Perhaps the best quality instrument of this prolific range of French made 4½” dialled instruments, the movement representing the most refined of the Vidi pattern from this era. Of particular interest is the pressure sensing capsule, specifically its quality and construction. The performance characteristics of this capsule being typical of early metallurgy in capsule construction, showing a notable reduction in resolution pressures below 28” but having good accuracy across the standard range 28 – 31”Hg

This is clearly an instrument of premium quality. Apart from the special capsule, the adjustments for gain and rate are particularly finely executed, the use of squares in common with Richard Freres barographs, the skeletal index a unique design to Bourdon and Richards instruments, the dial design, fonts and script “Aneroid Barometer” all intensely characteristic to this line of making.

Taking into account these similarities and obvious excellence in making it is our view that this instrument was most probably the work of Jules Richard.

It should be noted though that Naudet also used squares for adjustments and that the movement bears some resemblance to those produced by Naudet. This might not be so unlikely as it is known that Naudet were making fine aneroid movements ahead of Jules Richard – they would have been an important reference for this new line from the Richard stable.

Very rare, clearly manufactured in small numbers to this precise pattern, in generally fine condition, this is very much a collector’s item and an important milestone in the development of the aneroid barometer.

Dimensions: 5” diameter x 2” deep

Stock No: BA2015

Price: SOLD