A good gilt lacquered brass weather watch aneroid pocket barometer forecast prognosticator No R/3219 by Negretti & Zambra, London, c1924

Weather watch having three piece silvered and die struck dial, the upper and outer part calibrated in inches of mercury with a standard barometric range from 28” – 31” and divided to 1/10th”, the lower outer part with wind directions on the compass points, bezel operated setting at “Direction of Wind.” The inner part, rotated from the crown, with short altitude compensation scale to top, three apertures for falling, rising and steady pressure revealing the Arabic letter codes, “N&Z logogram,” “Patent 6276/15,” serial no. “R/3219,” and signed by the maker at lower part.

Conventional 1st quality Vidi pattern movement driven from a single 1” capsule tensioned on a C spring, contained in a semi drum form case, altitude correction scale to circumference, circular interpretation guide, and calibration port to verso.

Altogether with its correct leather over timber green velvet lined case with a further circular celluloid interpretation guide to inner lid. Snap closure on a button release. Gold block initials “AEJ” to lid.

Condition: The subject of a full service, conservation and calibration under laboratory conditions. The movement working well with excellent sensitivity and progression, and very commendable accuracy – see attached performance chart. 

The dial with clear signs of ageing, some losses and minor abrasion. The case retaining virtually all its original lacquer finish, remaining bright and vibrant. Very minor loss to extreme edge of bezel. All adjustments working freely with just sufficient inherent resistance to prevent accidental alteration of settings.

The leather case the subject of some conservation, including a replacement release button and leather over, small section leather inside lid adjacent to hinge. Historic repair to hinge which appears sound. A slight mismatch between top and bottom of case.

Comments: It has been some time since we have been able to offer one of these most sought after of instruments. This one is exceptional overall in that the aesthetics and function are very good, and it is also in very original condition.

The weather watch is a simple weather forecasting barometer. The trend in barometric pressure is noted as steady, rising or falling, and this will select the aperture at the centre of the instrument dial. Wind direction is selected by rotating the the bezel until the desired direction is opposite the marker arrow “Direction of Wind”. The letter in the appropriate window is then noted, and the corresponding forecast will be found on the verso or on the celluloid disc in the lid. There are 26 potential forecasts.

A correction for altitude or station height may be made by rotating the verso, aligning the marker arrow with the known height. This will correct the pressure reading on the dial to sea level, a correction of approximately 1” of mercury is equal to an elevation of 1,000ft.

These instruments are the Rolex of the pocket barometer world, and are certainly the best known and most sought after of these generic instruments. Very much a collector’s piece in this condition.

NB: The orginal instructions shown are in the Vavasseur Archive – a copy will be provided with this instrument.