Thematic Auction in Geneva:The Evolut...

Hotel Noga Hilton, Geneva, Nov 16, 2002

LOT 287

Breguet, No. 1149, sold to Bureau de Longitude circa 1870 for 2400 francs.Exceptionally rare and important mahogany four-day going Chronomètre Compte Secondes with 4-day power reserve indicator for the going train and 8-hour power reserve indicator for the dead-seconds Break-Circuit train (Survey and Mother Clock).

CHF 25,000 - 35,000

EUR 17,000 - 23,000

Sold: CHF 34,500

C. Rectangular, mahogany, hinged door at the back, gilt bun feet with additional four at the back door for working in a horizontal position, ivory pushbutton at the top for engaging or disengaging the Mother Clock. D. Silvered, set at the top of gilt plate, Roman numerals, outer minute track, winding indicator at 12 o'clock, subsidiary seconds, sector with winding indicator for the Mother Clock below. Blued steel "Spade" hands. M. Going train: 89 mm., brass, circular, reversed fusee with maintaiing power and chain on single bridge, train and escapement on separate circular plate, Earnshaw type spring detent escapement, bimetallic compensation balance with two circular sliding temperature weights, free-sprung blued steel helical balance spring with terminal curves, escapement jeweled and capped, diamond endstone on the balance, additional pivoted detent for controlling seconds-beating mechanism activated by unlocking action of the escapement, mechanism disengaging the seconds-beating trin when the going train power goes to zero. Dead-seconds Mother Clock movement: rectangular, brass, fusee with maintaining power and chain, X-shaped jeweled fly with finely adjustable momentum of inertia, controlled by the pivoted detent from the going train meshing with contact breaker wheel giving impulse once a second, whose width is controlled by a knurled knob, self-cleaning contacts.Signed on the dial.Dim. Height 28 cm., width 19 cm., depth 13 cm.


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Grading System
Case: 3

Good
Movement: 3*

Good

Overhaul recommended, at buyer's expense
Dial: 3 - 01

Notes

The clock was begun on April 19, 1861 when Breguet paid Monsieur Klaftenburger for the going train ebauche. On February 1, 1867 work began on the clock and it was finished on June 5, 1869 when the mahogany case made by Bailleux was delivered.The Break-Circuit (Survey) Chronometer was designed to assist in surveying and mapping operations as well as in solar observations and scientific experiments in remote areas that require accurate and audible time signals.However, the Breguet system seen in this clock differs entirely from early Break Circuit mechanisms. These were simple, consisting of an additional contact wheel mounted on the fourth or escape wheel arbor and a simple spring-loaded contact breaker.In the Breguet system the extra load on the going train is kept to a minimum. Furthermore, the clock is very unusual because of the effort devoted to ensuring that practically every function could be adjustable and that the length of the impulse be as short as possible. To this end, one more detent was added, with both contact ends jeweled, (one of them is also adjustable). The function of the additional train is to control the contact breaking as well as the strength of the impact on the detentIt has previously been thought that the first break-circuit mechanism was installed by the Negus brothers, chronometer makers from New York. In 1874 they published their "Description of and Rules for Using Break Circuit Chronometers". About the same time Kullberg installed a Break Circuit in one of his chronometers. At the time, the system was generally considered useless because of the extra load on the escapement adversely effecting the rate.It appears that at the same time, or perhaps even slightly earlier, Breguet was also seeking to implement the idea of the Break Circuit. One branch of the Breguet family specialized in the telegraph, and it may well be that their work contributed to this instrument, for the principles are similar. For the moment,in any case, on the virtue of this instrument, it would seem that Breguet was the first to produce a Break Circuit clock, by a margin of five years.It should be mentioned that Louis-Clément Breguet, the grandson of Abraham-Louis, and at the time in charge of the Breguet firm, had been a member of the "Bureau de Longitudes" since 1862. He had experimented with electromagnetic devices since the 1850's. In 1856 he utilized electric power to wind weight-driven clocks.