external coil spring
brass, carved wood, glass, nickel silver, plastic, steel
Before us is a rare and striking example of a late 19th-century French aneroid barometer, distinguished both by its unusual dial configuration and by the sculptural character of its wooden case.
Case
The barometer case is carved from solid oak, executed in high relief with deep undercutting, almost sculptural in its treatment. What we see here is an organic, imaginative composition in the spirit of late French Neo-Rococo, in which the carver deliberately departs from strict ornament toward an almost living, fluid form—on the boundary between vegetation, shell, and anatomy.
The foundation is rocaille. Classical elements are clearly present: shell-like scrolls, asymmetry, and flowing, continuous lines. Yet the carver moves beyond traditional ornament: the forms seem to “grow” and expand, losing clear botanical definition; in places, they take on nearly zoomorphic, even anatomical suggestions. The result is an impression not of ornament, but of living matter in the process of transformation.
Thus, the carver has created not merely a decorative case, but a metaphor of natural force contained within wood—as if the material itself were “growing” into the form of the instrument.
Dial
The dial is made from one of the earliest forms of plastic—celluloid—produced from nitrocellulose (formed through the action of nitric and sulfuric acids on plant-based material) combined with camphor.
The material closely imitates elephant ivory, a resemblance clearly visible in the present example: the surface displays a characteristic “living” texture, with soft, wavy, alternating striations and a sense of depth not found in homogeneous materials.
This effect was achieved through a complex process: sheets of celluloid, tinted in different shades, were layered and compressed under heat to form a solid block, from which the dial was then shaped.
The defining feature of the barometer is its semi-circular (180°) dial, a configuration rarely encountered in aneroid instruments.
Combined with the rectangular thermometer plate positioned directly beneath it, this creates a striking visual effect of a “broken” or “split” barometer. The composition is so unconventional that the eye—accustomed to the circular form of both clocks and barometers—does not immediately recognize the object as a unified instrument, especially when paired with the expressive, almost chaotic carving of the case.
The scale is engraved directly onto the celluloid dial and calibrated in centimeters of mercury over a range of 73–79 cm. It is further enhanced by French textual weather indications.
The dial is protected by a flat mineral glass. At its lower edge is a brass setting pointer (trend indicator) with a knurled adjustment knob, allowing the user to mark and track previous pressure readings.
Movement
The movement has been specifically adapted to accommodate the unconventional dial shape.
At its core is an aneroid capsule made of nickel silver, tensioned against a substantial brass lever supported by a coil spring.
Due to the semi-circular dial, the pointer arbor is displaced from the center of the mechanism toward the lower right. Motion is transmitted from the main lever through a crank lever and then to the pointer arbor via a fusee chain—a solution requiring precise adjustment and characteristic of more sophisticated constructions.
Thermometer
Beneath the barometer is a spirit thermometer, housed within a wooden frame and protected by flat mineral glass.
The capillary is mounted on a rectangular celluloid plate, matching the main dial in material. It bears an engraved centigrade scale, supplemented by textual heat indications (Glace, Tempéré, Bains), typical of French domestic instruments of the period.
Conclusion
This barometer represents a rare synthesis of engineering ingenuity and artistic exploration. Its unconventional semi-circular dial, complex mechanical adaptation, and expressive carved case elevate it beyond a purely utilitarian instrument, placing it closer to the realm of decorative sculpture.
Such pieces are especially valuable as evidence of a moment in history when the meteorological instrument became not only a tool of measurement, but also a vehicle for artistic expression.