Weather watch pocket barometer with 2” tri-concentric silvered dial, the outer section calibrated in inches of mercury with a range from 28” – 31” marked “Sea Level,” the lower portion with settings for “Direction of Wind,” the inner rear dial with letter codes visible through three semi-curved rectangular windows cut into the centre forward dial positioned at 3, 6 & 9 o’clock, further marked with altitude correction scale “+/- 500FT,” “N&Z monogram, “Patent 6276/15,” serial “No R/872,” and signed in full by the maker “Negretti & Zambra.”
Fine blued-steel pointer set beneath bevelled glass. Rotating bezel, enabling setting of wind direction and causing interpretation codes to alter in the three windows. The case circumference with altitude correction scale from 0 – 3,000’; rear section may be turned causing the whole movement to turn within the case, thus altering the position of the pointer relative to the dial. Verso of the case with compensation screw set at 8 o’clock and letter codes set to forecasts, also included upon a celluloid disc fitted to the inside of the leather case. The centre dial rotated via the crown. Suspension ring. The movement driven by a single capsule with bimetallic compensation. All contained within its original ox-blood Moroccan leather over wood and green velvet lined case. The case retaining virtually all its original lacquered finish, the leather case in excellent condition.
To use the weather watch, first note whether the barometric pressure is steady, rising or falling. Then set the station altitude using the circumferentially-marked scale and rotating the rear of the case aligning the index point the correct station height. Note the direction of the wind by rotating the bezel so that the arrow for wind aligns with the correct compass cardinals. Finally, read from the window marked “Fall” “Steady” or “Rise” as appropriate – the letter shown can then be related to the forecaster messages on the rear of the barometer or on the celluloid disc.