A very good aneroid pocket barometer altimeter no. 1962 with loupe, retailed by Norris, Birmingham c1868
Pocket barometer having 1¾” silvered and engraved dial, the outer bezel driven altimetric scale calibrated in feet with a range from 0 – 15,000ft divided to 100ft, supplementary higher and lower scale +/- 1,000ft, the barometric scale calibrated in inches of mercury with a range from 17” – 31” and divided down to 1/10th”. The upper part with standard meteorological terms and “Compensated,” the lower signed by the retailer, “Norris, 13 Bull St, Birmingham.” Blued steel pointer, bevelled glass with loupe.
Conventional movement, marked serial “No. 1962,” of Vidi form driven from a single 1″ capsule tensioned on a C spring. All contained within a ribbed drum form brass case with extension and bow, calibration port to verso.
Together with its correct brown leather over timber, clamshell pattern royal blue silk and velvet lined case, snap closure on a button release.
Condition: The subject of a full service, conservation, and calibration under laboratory conditions. The movement working exceptionally well with excellent accuracy to 25” Hg; at lower pressures, the expected error appears. Sensitive and with good progression.
The dial very good with evidence of slight ageing, minor mark to centre at 3 o’clock, the glass remaining clear and un-chipped. The brass case clean and retaining much of its original lacquer, some wear to circumference and small losses to verso.
The travel case structurally sound, evidence of an historic minor repair to leather over button, otherwise good lustre generally. The fabric interior with some discolouration to lid silk, the base velvet with some loss to colour. The catch and hinge in good condition.
Comments: A very good example of an early pocket barometer, original and working exceptionally well. The addition of a loupe to the glass enabling clearer interpretation of the barometric reading – this is an addition rarely seen on English instruments. In addition, the colour of the travel case linings is more usually seen in continental examples.
The movement has more than a passing resemblance to those by both Callaghan and Negretti & Zambra, but with shades of French manufacture. Research continues!
Benjamin Norris is reported as working from 13 Bull St, Birmingham from 1862-1868, when the business was taken over by John Place.
Dimensions: 2¼" wide x 2¾" long x 1⅛" deep
Stock No: PB2303