Barometers Realm

This Enamel-Dial Pocket Barometer, manufactured by Antoine Redier around 1880, is housed in a compact, circular case made of nickel-plated brass. At the top of the case is a suspension ring intended for attachment to a chain—analogous to those used with pocket watches—allowing the instrument to be conveniently carried during travel and outdoor walks.

The case is fitted with a knurled rotating bezel, into which a relatively thick mineral glass with a neatly finished, even bevel is set. On the inner side of the bezel, a long metal rod with a pointed tip is mounted, serving as a barometric trend indicator: by rotating the bezel, the user can mark a previous reading and visually track subsequent changes in atmospheric pressure.

Behind the glass lies a striking bright white dial, made from an enameled plate—a feature uncommon in pocket barometers but well established in pocket watches. Redier, being a trained watchmaker, transferred this horological practice to his barometric instruments. The dial bears a concentric barometric scale, calibrated in centimeters of mercury over a range of 57–80, in accordance with the metric tradition of measurement. Along the outer edge runs a textual weather indication in French, rendered in elegant typography. The inner portion of the dial carries a non-linear altimetric scale, graduated in meters up to a maximum of 2400 m. At the lower part of the dial appears Redier’s well-known maker’s mark, “ARED”. The dial itself is secured to the case by two tiny screws, discreetly positioned at the sides.

The indicating pointer is made of blued steel (heat-blued) and features a small circular aperture at its tail, likely inspired by Breguet-style hands with a crescent or ring motif.

The instrument is driven by a conventional continental cantilever movement, based on a rack-and-pinion system acting on the pointer arbor. Deformation of the approximately 30-mm aneroid capsule, made of nickel silver, is initially transmitted via a push-rod to a brass rocking lever, from which the motion is further conveyed through the gearing.

An additional constructional feature is the removable rear cover, made in the manner of contemporary watch cases. A small triangular notch is provided to allow the cover to be levered off with a tool. From a practical standpoint, this solution offers no functional advantage for the operation of the barometer; on the contrary, such an opening may facilitate the ingress of dust and small insects into the case, potentially leading to contamination of the mechanism over time.

Overall, this Redier pocket barometer represents a successful synthesis of compact form, sound mechanical design, and refined graphic sensibility, characteristic of the finest French meteorological instruments of the late nineteenth century—objects conceived not only for practical use, but also for visual and material appreciation.