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Object Overview
This is the earliest aneroid barometer from around 1850, bearing the serial number 994, a model patented by the inventor in 1845.
The barometer is housed in a solid brass case with a warm golden hue. The top section features a sturdy hanging ring. One of the most remarkable details is the bezel, adorned with an intricate pattern resembling interwoven threads or a scale-like motif. This is a highly interesting decorative element, characteristic of early aneroid bezels found in cylindrical brass cases. The ornamentation was likely created through engraving or embossing, adding an extra layer of visual depth to the instrument.
The dial is made of glazed cardboard, set within a brass frame featuring a golden reflective ring. It maintains a strict and minimalist design, with delicate black inscriptions on a light background. The barometric scale, arranged concentrically, is calibrated in centimeters of mercury, ranging from 57 to 79 cm. The upper part of the scale contains weather condition inscriptions in a classic serif font:
994
early Vidie
brass, cardboard, copper, glass, iron
At the bottom of the dial, the inscription “Baromètre Anéroïde” is written in italics, with the serial number 994 placed between the words. The dial is protected by a thick mineral glass with beveled edges, giving the instrument an elegant appearance. Behind the glass, there is a brass trend indicator, manually adjusted via a knurled brass knob at the center of the glass. This allows the owner to manually mark the current pressure and track trends over time.
At the heart of the movement is a sensitive aneroid chamber (Vidie capsule) made of copper. The walls of the capsule change height in response to atmospheric pressure fluctuations. To transmit and amplify this subtle movement, a large iron plate is attached to the top of the capsule, with its edges resting on supports. A main lever extends from the right side of the iron plate, functioning as a continuation of the plate itself. This lever presses against a powerful helical spring.
At the base of the mechanism, the lever connects via a hinge joint to a secondary short lever, which further amplifies the movement. This short lever transmits motion to a vertical lever, whose end is linked by a chain (similar to a bicycle chain) to the indicator shaft, which rotates the pointer. Around the indicator shaft, there is an additional hairspring, which maintains slight tension to eliminate pointer backlash.
Unfortunately, time has not spared the barometer’s mechanism. The chain connecting the vertical lever to the pointer shaft is broken, and signs of repair are visible in some lever joints. The aneroid capsule has a small dent, likely the result of a fall, which is also evident from marks on the exterior brass case. However, the aneroid capsule has remained airtight and functional.