4,800 CHF
Breguet, No. 4107. Made in September 1938, sold to the French Aéronautique on December 30, 1938, for 15,800 francs. Fine and rare keyless “Sidéromètre Breguet Type 101” splitseconds chronograph, Breveté S.G.D.G., froma series of 25 pieces. Painted aluminum box, lined with felt insulation. Three fixing brackets are riveted to the outside. There is no case, the movement being fixed to the underside of the dial-plate, the latter engraved with operating indications. White painted with outer seconds divisions and three apertures for the digital degree indications. Blued steel counterpoised hand. Notes The Sidéromètre, designed in the late 1930s, runs at sidereal, rather than mean time, then converts this into degrees, minutes and seconds of Earth’s rotation. The center-seconds hand rotates in the time the Earth rotates through 1° in relation to the stars. The Earth’s angular rotation is recorded by the numbered discs appearing in the dial apertures: degrees are shown on the right side, tens of degrees in the center, and hundreds of degrees on the left. Since the temperature in an airplane of the period could drop very low at high altitudes, it was necessary to prevent rapid cooling of the inside of the box, which might cause condensation in the mechanism. Though accurately compensated, the watch would have been subject to a transient response due to rapid and extreme temperature change, and this had to be prevented.
Auctioneer:
Antiquorum
Date:
2008-11-16
