Excellent Vacheron Constantin pocket watch, circa 1900.
It's equipped very high quality movement with chronometric Guillaume balance and rarely seen Brandt's micrometric regulator.
Instead of steel used in usual cut/compensated balance, Guillaume balance uses special nickel alloy, which provides much better stability in various temperature conditions.
Guillaume balance wheel was mostly used in chronometer watches as it's a complex and expensive part of the watch.
For example in the entire 1967 V&C parts catalog it's the most expense item at CHF 20,500 or $4,735 USD at the time..
The watches with similar oscillating part was called by Vacheron Constantin as "Chronometre" or "Demi-Chronometre" depending whether it was sent to Geneva Observatory for competition or wasn't.
Even now, after 115 years, this watch demonstrates great consistency of timekeeping. But please note, that now it's not adjusted for different positions, time keeping may wary depends o.
I included two photos of Vacheron Constantin watches with similar movements that was sold by Antiquorum in Geneva in 2005.
The watch is in descent condition.
Dial seems to be free from hairlines.
Case bears Vacheron Constantin hallmarks as well as 18k gold hallmarks and is numbered.
Dust cover bears Vacheron Constantin signature and Parisian retailer address.
Case has several minor dings and dents, please see photos.
Movement is in good running condition and keeps great time
Not for sale