A fine interesting and substantial second generation silver cased aneroid pocket barometer by Negretti & Zambra No 1725 for the 2nd Duke of Sutherland c1868

Silver pocket barometer having 1¾” silvered and die struck dial, the outer altitude scale calibrated in feet with a range from 0 – 10,000ft divided down to 100ft, inner barometric scale calibrated in inches of mercury with a range from 21” – 31” divided down to 1/10th. The upper part marked “Compensated,” the lower signed by the maker, “Negretti & Zambra, London” with serial no. “1725.” Blued steel pointer, rotating bezel with barb index, bevelled glass.

The second generation finely poised miniaturised movement with decorated chassis driven from a single 1¼” diameter nickel alloy capsule tensioned on a coil spring. The cock and spindle mounted to lower milled section, the bridge marked “010” and “T” with steel bracing, the verso struck “3.”

All contained in a substantial hallmarked semi barrel form, ribbed sterling silver case, engine turned finishers, the verso with Whiteside-Cook pattern calibration adjustment, full plate engraved coat of arms for the 2nd Duke of Sutherland. Pendant and bow.

Presented in its correct burgundy leather over timber, plum velvet lined travel 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 maximum error of ⅓” across the scale, see performance chart from dynamic test.

The dial very clean with minor marks only. The silver case bright, clean and with good lustre.
The leather case structurally sound, the external leather with some wear and impressions, otherwise with high finish and excellent colour. The fabric interior sound with minor wear and good colour.

Comments: A truly impressive, unique representation of Negretti & Zambra’s early pocket sized instruments – a substantial weight in the hand and certainly one of if not the most impressive coat of arms to the verso that I have examined, a work of art in itself.

These instruments are rare. In this condition and with this provenance unique.