A good early French 4½” dialled aneroid barometer and thermometer no 19921 by Lucien Vidie c1860

Aneroid barometer having 4½” silvered and engraved dial, the upper part with semi circular barometric scale calibrated in inches of mercury with a range from 27.5” to 31.5” divided down to 1/50”, standard meteorological terms and the legend “Aneroid Barometer,” the lower part marked “Fahrenheit’s Thermometer” with serial no. “19921” below, semi-circular thermometer, the register calibrated in degrees Fahrenheit with a range from 20° to 100°, divided to 2°. Blued steel pointer, deep bevelled glass with gilt index.

Conventional Vidie pattern movement driven from a transitional 80mm x 10mm soldered nickel alloy capsule tensioned on transversely steel bar-braced C spring. The whole presented in a brass belled drum form case, pendant and suspension ring, calibration port to verso.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test, the movement working well with good sensitivity and accuracy to less than 0.1” across the range. The dial very clean with some signs of ageing to periphery, the brass case with good colour, some minor dents.

Comments: This is an instrument that would normally be found marked “Dent, Paris” – the fact that this dial is not so marked is unusual and a confirmation that not all Vidie’s output was retailed by Dent. The movement is also of interest and manufactured at a time when Vidie was clearly experimenting with a number of technical developments to the movement. This one – third pattern Vidie movement – shows the C spring bracing bar and the hook-and-plate connection of the capsule to the C spring.

Historically of interest, this is one of the first generation of aneroid barometers manufactured by the instrument’s designer, and very much a collector’s piece.