Chronomètre à tourbillon

Historical significance

• Tourbillon chronometer. Dome engraved: Chronomètre à tourbillon Echappement libre à ressorts Trois levées en pierre et huit trous en rubis Spiral sphérique isochrone Balancier compensateur. Movement signed: Fic Ls FAVRE BULLE AU LOCLE Fecit. Circa 1820.
• The case is polished silver. The time is set by using a small lever on the left of the pendant, on the dial side, which stops the movement by blocking the tourbillon cage.
• The white enamel dial has black painted Roman numerals for the hours, an additional small dial at the top for the seconds and, at the bottom, a thermometer dial with the Réaumur scale.
• The polished steel tourbillon carriage contains a spring detent escapement, and a compensation balance fitted with two trapezoidal-shaped weights plus two gold screws. The spherical balance spring has no index. A small lever under the tourbillon blocks the third wheel, thus making it possible to remove the complete carriage without letting down the mainspring. The movement is almost identical to the chronometer made by Louis-Urban Jürgensen (Inv. I-496), which is also part of the MIH collection.
• The thermometer, which has a bimetallic strip, is under the dial.

Sources & references

1. Musée international d'horlogerie, online collection record, inv. I-198: https://collection.mih.ch/fr/collection/item/38015/

Where sources disagree, the disagreement is stated rather than resolved silently.