Antique aneroid barometer having 4¼” silvered, engraved and engine divided dial calibrated in inches of mercury with a range from 25 – 31 divided to 1/100^th”, the upper part signed “Elliott Bros, London,” the lower marked “Compensated for Temperature,” gilt reflector ring with dial attachments, blued steel pointer with added knife at tip, gilt index with knob, deep bevelled glass, Dent-style herringbone bezel.

High quality movement driven from an early pattern 3” nickel alloy capsule tensioned on a C spring mounted to cast and machined bridge supported in brass end pillars with associated bearings. The cross shaft with spherical kinetic mass having longitudinal adjustment, twin square headed screws for adjustments to gain and relative position, primary lever the subject of modification by Elliott Brothers with the addition of adjustable bi-metallic compensation. All raised over a circular iron chassis.

All contained within a bell top drum form case, extension post and suspension ring, the verso with compensation port. The verso struck with the logogram “PHBN.”

Condition: The subject of a complete overhaul, conservation and calibration under laboratory conditions. The dial with some ageing, shading, otherwise clean and crisp, the bezel slightly deformed, original glass with minor abrasions, the case generally crisp retaining most of its original lacquered finish, some wear and minor dents/depressions. The movement working well across the range with excellent sensitivity and good progression, see cperformance chart.

Comments: This antique barometer is a good comparison to that example numbered 14 also shown on the site. It is clearly later as the numbers would suggest, and instrument no. 14 is dated positively on the verso to 1864. There are too many similarities between the two for there to have been latter modifications or additions, and they provide good evidence of the work undertaken by Elliott Brothers in the application of temperature compensation. The general engineering and appearance of this movement suggest a process of refinement.

Undoubtedly originating from the French maker Pertuis Hulot & Naudet, this was a wise choice since Naudet were amongst the finest instruments of their class at the time. The intention here is clear – take a very fine movement and modify it further to produce an instrument of the most reliably accurate nature, evidenced by the finely divided dial, the knife addition to the pointer helping eliminate parallax and enabling the highest resolution, and the well-engineered modifications for temperature compensation. Unlike the earlier instrument, the temperature compensation arrangement added to the primary lever is steel, providing a greater difference in coefficient of expansion.

A very important and unusual instrument, a fascinating commentary on the development and innovation of the aneroid barometer system, in well above average condition. A collector’s piece.

Dimensions: 

Stock No: BA1730

Price: Vavasseur Archive – not currently for sale