Miniature pocket barometer having 1¼” silvered and engraved dial, the outer rotating altimetric scale calibrated in feet with a range from 0 – 5,000ft and divided to 100ft, inner fixed barometric scale calibrated in inches of mercury with a range from 25” – 31” and divided to 1/10”. The upper part marked with standard meteorological wording, lower portion marked “Ross, London” and “Compensated.”Fine blued steel pointer beneath bevelled glass. Conventional 1st quality movement by Negretti & Zambra driven from a single ⅞” nickel alloy capsule tensioned on a coil spring.
All contained within a semi barrel form silver case with engine turned bezel and verso, the latter with calibration port and blank cartouche, extension post and suspension ring. Hallmarks for silver, London, 1880 and Thomas Cobb.
The whole contained within its original high quality leather over wood, burgundy velvet and purple silk lined case. Snap closure on button release.
Condition: The subject of a full service, conservation and calibration under laboratory conditions, the pocket barometer altimeter working well with good sensitivity and progression, see performance chart. Overall very crisp, the dial with very faint scratches to centre, the crystal chip-free. The silver case with slight mark to side caused by leather case release. Leather case sound, the button release working correctly. The lid silk replaced and some restoration to case side at hinge.
Comments: Silver pocket barometers are perhaps amongst the most attractive of these instruments, and certainly the hardest to find – the miniature variant rarely seen. In addition, this has an unusual and very high quality finish to the leather travel case.
A very attractive and unusual pocket barometer from a top maker for sale by another. Very collectable.
Dimensions: 1¾” diameter x 1” deep
Stock No: PB1822