Pocket barometer having 2½” silvered and struck stepped dial, the outer scale with an altitude range from 0–8,000ft, the inner scale calibrated in inches of mercury with a range from 23–31. The upper portion of the centre dial marked with standard meteorological wording “Stormy, Rain, Change, Fair and Very Dry,” “Compensated,” and serial no. “801,” the lower portion with curved thermometer with a Fahrenheit scale from 20-120 degrees. Very fine blued steel pointer set beneath a bevelled glass maintained within a rotating engine-turned bezel with index. Conventional compensated 1¼” capsule-driven movement on a substantial cast iron chassis, contained within a gilt brass drum-form case. Case extension with bow. Barometer compensation port and screw set to verso at 8 o’clock, having hand-scratched annotation “J. Cocks, 1866.”
The pocket barometer retaining traces of its original gilded finish, the dial in excellent clean condition, the bevelled glass unmarked. Serviced and calibrated, the barometer altimeter functions well with good progression and sensitivity, the rotating bezel turning smoothly.
Although unsigned, this very high quality instrument is almost certainly the work of Negretti & Zambra, and the unusual finely shaped pointer is near identical to that shown in the illustration taken from the Negretti & Zambra Complete Catalogue of 1886.
Dimensions: 2¼” diameter x 1″ deep
Stock No: PB0905