Very rare and historically important A. Lange & Söhne No. 72028 silver openface keyless 1/2 (half) second observation pocket chronometer, manufactured in 1915.
Produced in highly limited numbers by A. Lange & Söhne, this pocket-watch chronometer with central second fulfilled specific scientific requirements. The watch was constructed with 14400 half-oscillations in one hour, so that the seconds hand is able to make half seconds jumps. The central second going train is conventionally laid out with a motion-work of the gold wheels above the movement bringing the shaft of the second hand through the centre-wheel. For a detailed description see “A. Lange & Söhne The watchmakers of Dresden” by Reinhard Meis p. 214 or “Die Uhren von A. Lange & Söhne Glashütte Sachsen” by Martin Huber p.102 ff, 5th ed.
Signed A. Lange & Söhne, Glashütte b/Dresden, No. 72028, manufactured in 1915, Modified cal. 21”’ three quarter plate gilt-finished movement, spring detent escapement, bimetallic compensation balance with gold poising screws, blued steel helical hairspring, free sprung regulator with diamond endstone, finely engraved balance cock, silver cuvette, silver dial, Roman numerals, outer railway five minute divisions, central seconds, plain Jürgens case, pink gold hinges, case, cuvette and movement signed and numbered, dial signed.
The watch is sized at 61mm, which is normal for a scientific observation chronometer, but considerably larger than any pocket watch you will find, it features a half second jumps, regulator with diamond endstone, spring detent escapement and extremely rare for Glashütte central second hand complication.
Auction sales results for similar watches:
- Christie’s ‘Important Watches’, Geneva, 17 November 2008, Lot 37 – 40,000 CHF;
- Christie’s ‘Important Watches’, Geneva, 11 May 2009, Lot 265 – 40,000 CHF;
- Dorotheum ‘Wrist and Pocket Watches’, Vienna, 28 Nov 2014, Lot 161 – 36,000 USD;