Geneva, Nov 07, 2021

LOT 513


CHF 20,000 - 40,000

HKD 170,000 - 338,000 / USD 21,700 - 43,400 / EUR 18,700 - 37,300

Sold: CHF 47,500

An extremely fine and rare, manual wind, silver chronometer pocket watch with power reserve.

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Grading System
Case: 3-8


Slightly scratched

Movement: 3*


Overhaul recommended, at buyer's expense

Dial: 2-50-01

Very good


HANDS Original

Brand Patek Philippe

Model Heure Exacte

Year Made in 1902, sold in October 1941

Case No. 235554

Caliber 20’’’, chronometer

Dimensions 59 mm, 145 x 116 x 67 (fitted case)

Signature Dial, Case and Movement

Accessories Original fitted window display, extract from the archives, spare glass


In 1899, Dr. Charles Edouard Guillaume noted that steel with an addition of 44.4% nickel had a negative square coefficient of thermal expansion. This alloy, combined with brass in bimetallic lamina, makes its expansion almost quadratic. Balances with bimetallic rims made of anibal (an alloy invented by Guillaume: Acier au NIckel pour BaLanciers) and brass are usually called Guillaume balances, or, as their inventor called them, integral balances. When combined with special balance springs, they exhibit remarkable temperature stability, on occasion not exceeding 1/50 second per day at 10 degrees C.
The present watches are exceptionally well-made and adjusted for the Observatory Contests. Every detail, such as the special Guillaume balance with small wings at the arm for poising in the raw, before the screws are put in, which assures that temperature compensation adjustment will not affect poising, the superior polish of the steel parts, the olive jewel holes, and the very light undercut escape wheel with raised teeth, shows that these watches were very special ones.
As shown by the movement numbers repeated on the dial and twice on the movement, it confirms the watch was submitted to the observatory in 1904 where it obtained a “mention honorable”.