Barometers Realm

This barometer is part of the private collection of our friend and fellow collector Michael Böttcher (Germany). All photographs were kindly provided by him.

Before us is an Open-dial Metallic Barometer of the Bourdon type, produced by the Parisian workshop of Léon Arrouit during the period of active dissemination of metallic barometers following the expiration of Eugène Bourdon’s patent (1870–1878).

The case is executed in a compact drum-shaped form in brass, displaying a warm golden tone. Its construction is highly restrained and functional: an extremely thin, undecorated bezel—emphasizing the utilitarian character of the instrument—holds a flat mineral glass with a faceted edge. At the top of the case, a suspension ring is provided, allowing the instrument to be mounted or hung in an interior setting.

The dial is open and made of cardboard, designed in a manner typical of French aneroids. The concentric barometric scale is graduated in centimeters of mercury and supplemented with textual weather indications in French. The typography deserves particular attention: the inscriptions are executed in elegant serif typefaces with pronounced contrast in stroke weight, while individual words vary in size and emphasis, creating a lively and rhythmically arranged composition around the circumference of the scale. Such diversity of typographic treatment is characteristic of French instrument graphics of the period and reflects an effort to unite scientific function with the visual culture of the object.

The central portion of the dial reveals the mechanism, allowing the operation of the instrument to be observed. The construction is based on the Bourdon tube—a curved, elastic metal tube of oval cross-section, partially evacuated, which deforms under atmospheric pressure. Changes in its shape are transmitted through a simple yet precise system of levers to the pointer axis. In this example, a sector transmission is employed, featuring a brass toothed rack characteristic of early constructions. The pointer is made of blued steel and terminates in a crescent-shaped counterweight.

On the brass plate of the mechanism appears the workshop mark—a characteristic “AR” punch within a diamond-shaped cartouche, rendered in cursive script—as well as the initials “L.A.”, attributable to Léon Arrouit. These markings confirm the attribution of the instrument and connect it to a small yet technologically active Parisian workshop that participated in international exhibitions in the late 1870s.

Thus, this barometer represents a striking example of a transitional stage in the development of metallic barometers: compact, functional, and free from excessive ornament, it demonstrates both the technical maturity of the Bourdon principle and the distinctive culture of scientific instrument design in France of that period.