Description
A very rare chronometer with Eiffe’s auxiliary temperature compensation is a gold open face case. Full plate gilt keywind fusee movement with blue steel Harrison’s maintaining power. Engraved gilt barrel bridge with polished steel ratchet, click and spring. Engraved cock with diamond endstone, screwed to the table Eiffe’s auxiliary temperature compensation device. Unusual heavy compensation balance, the timing nuts on the inside of the rim. The bimetallic rims "D" shaped in section and the steel blued. Sections of the rim slotted to allow the screws to be held securely. Freesprung blue steel helical hairspring. Earnshaw type spring detent chronometer escapement, jewelled impulse pallet. Screwed in jewelling, escape pivots with endstones. Unusually the centre pinion is jewelled in the pillar plate but a plain brass bush in the top plate. Signed white enamel dial with subsidiaries for power reserve and seconds, Roman numerals, blue steel seconds hand, gold hands with heart shaped tips. Substantial plain 18 carat open face case, maker’s mark "SC" in a rectangle.
A very rare chronometer by a maker of Irish descent in excellent overall condition. Constructed in a manner similar to marine chronometers of the period, details such as the minute wheel with a polished steel pinion mounted on a steel arbor. Eiffe's auxiliary temperature compensation was not often fitted and, when fitted, it rarely survives. Eiffe put a great deal of time and effort into its development. At the time the Admiralty were impressed by it as well as Molyneux's similar device. However its effect was probably limited and also mis-understood. Because of this the device was frequently discarded. This may be the only pocket chronometer retaining the device. Numerous variations of the device are shown in the small publication "Account of Improvements in Chronometers made by Mr. John Sweetman Eiffe". In addition the balance also appears to be one of the variations Eiffe introduced. Also known as James Sweetman Eiffe, 1804 - 1880. Born in Rutland Square, Dublin he was offered a commission in the army by his uncle. He instead pursued horology and devoted himself to perfecting the chronometer as a timekeeper. He was granted an award of ?300 by the Admiralty for his developments. He was elected a fellow of the Royal Astronomical Society in 1842. Casemaker Samuel Crafts, 9 Artillery Street, Bishopsgate Street.
