Pocket barometer having 1¾” silvered and engraved dial with barometric scale calibrated in inches of mercury with a range from 23–31, outer rotating altitude scale calibrated in feet with a range from 0–6,000, signed by the retailer to the upper part R & J Beck, 31 Cornhill, the lower part marked “London” and “Compensated.” Blued steel pointer set beneath a bevelled glass. Early pattern Negretti & Zambra lacquered brass 1¼” capsule driven coil spring tensioned movement with bi-metallic compensation to primary lever extension. Barrel form case, the engine-turned verso with vacant central cartouche, small setting grub screw to the circumference, pillar with suspension loop.
The whole contained within original oxblood grained leather over wood case having imperial purple velvet and cream silk lining. The lid lining with R & J Beck gold block logogram.
German silver, perfected in Birmingham in the 1830s, was the new wonder metal, comprising copper, zinc and nickel. The choice of German silver rather than Sterling silver might reflect a rising public interest in new materials, technology and metallurgy. From a commercial point of view at the time this instrument was very much at the forefront of technology, both in design and materials, setting it aside as significant. It is known that Beck, a preeminent manufacturer of top quality microscopes and photographic lenses, worked from the 31 Cornhill address between 1867 and 1880 – the early pattern Negretti & Zambra movement and the style of dial engraving suggest manufacture close to the earlier date. The rear of the case lacks a calibration/correction port so this is effected by loosening the grub screw to the circumference affording rotation of the entire back and movement relative to the dial – a very unusual feature.
Minor marks to the dial, the case with some marks and abrasions. The leather case with minor losses and wear, the silk and velvet linings in excellent condition. The instrument in good working order having been serviced and checked, the case cleaned. Original in all respects.
A fascinating early cooperation between two of London’s leading instrument manufacturers. An interesting comment on mid-Victorian technology and as such certainly very collectable.
Dimensions: 2½” diameter x 1″ deep
Stock No: PB0456