French, Royal Exchange, London. No.10119

Fine 2-day box chronometer with unusual balance. Circa 1845.

Case

Nicely figured 3-tier brass-bound box with green baize dust excluding inlay on the top edge of the bottom section.

Dial

Silvered dial signed French Royal Exchange LONDON No. 10119 with subsidiary seconds dial, showing half seconds, and state-of-wind indication below XII, original blued-steel hands.

Movement

Fullplate fusee movement signed French Royal Exchange LONDON No. 10119, an additional feature not usually seen. Earnshaw spring-detent escapement of Pennington's 'dovetail' form, the detent with gold passing-spring. Unusual form of compensation balance, each bimetallic arm with a brass affix at the free end allowing for the extra weight to be finely adjusted, with 9-turn blued-steel helical balance-spring.

Box approx 6 1/2 inches (16.5 cm) square

Probably retailed by John French, eldest son of the Irish born watch and chronometer maker (Santiago) James Moore French, who succeeded to the business when his father died in 1842. John French looks to have died at a tragically young age, the business being continued from the same address by his brother William.

A similar 2 day chronometer by French No 10816, appeared in the Royal Observatory's January 1937 listing of 'Chronometers for Disposal’.

As featured in David Penney’s recent Profile on Box-chronometers