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T140-25 · Pocket
c.1870
Object Overview
Presented here is a watch-size aneroid barometer with an ornamented dial, dating to around 1870, from the renowned English brand Negretti & Zambra. The barometer features a shimmering brass case with a diameter of just 47 millimeters. A distinctive feature of the case is its exceptionally thin (only 1.5 mm) fluted rotating bezel. This was made possible due to the absence of an integrated altitude scale. The bezel holds a flat mineral glass with a faceted edge, and on its inner side, a delicate setting index hand is mounted on a golden reflective ring.
One of the most remarkable aspects of this barometer is its silvered brass dial. Unlike traditional flat dials, this one is drum-shaped, with an open back. The dial is fully inserted into the barometer’s case, with its height slightly less than that of the case itself. The barometric scale, calibrated in London inches of mercury and divided into 20 lines, is arranged in a semi-circle in the upper part of the dial. Inside this scale, five textual weather indications are displayed.
At the bottom of the dial, an elegant and symmetrical Victorian decorative ornament is engraved—two curling branches with leaves, mirrored in design and extending outward from the center. The entire composition is adorned with light, graceful lines, emphasizing the classicism and refinement of the instrument’s design. Crowning the ornament is the brand name "Negretti & Zambra" and the serial number 15,167.
15167
external coil spring
brass, glass, leather, nickel silver, silvered brass, steel
Inside the case lies an exquisitely crafted early aneroid mechanism, meticulously designed with remarkable attention to detail. The aneroid capsule is pressed from above by a brass plate, which rests on an external helical spring, adjustable through a calibration port on the back of the case. A delicate main lever, crafted like a brass column with a capital, extends from the plate. A tiny linked chain, characteristic of early aneroid mechanisms, connects the movement to the pointer shaft. The entire mechanism is mounted on a circular brass base, which is adorned with compass-style engraving—a series of intersecting curved lines forming repeating wave-like or ring-shaped patterns. Unfortunately, it remains unknown whether this engraving was originally made by the master or added later.
The barometer is housed in a Morocco leather case with a snap lid, featuring an engraving of what is presumably the initials of the first owner, L.E.C.. Additionally, on the back of the case, a Masonic symbol—square and compasses—is engraved, adding an air of mystery to its provenance.
NEGRETTI & ZAMBRA have been makers of Aneroids since the expiration of the French patent, and in 1862 Mr. Glaisher, in his famous balloon ascent when he reached an altitude of seven miles September 5th, 1862, had with him one of their instruments. It was graduated down to five inches, and most carefully tested under the air pump before the ascent. Mr. Glaisher speaks of it in his "Travels in the Air."