Geneva, Nov 05, 2023

LOT 364

PATEK PHILIPPE, SWITZERLAND, REF. 738, POCKET CHRONOMETER, SO-CALLED “DECK-WATCH”, ESPECIALLY MADE FOR SCIENTIFIC PURPOSES, GUILLAUME BALANCE, ''RÉGLEUR FRANCOIS MODOUX'', SILVER

CHF 15,000 - 25,000

EUR 15,800 - 26,300 / USD 16,700 - 27,700 / HKD 130,000 - 218,000

Sold: CHF 18,750

A very fine, rare and large silver, manual wind open-face, keyless-winding, round-shaped, pocket chronometer, so-called “Deck-Watch”, especially made for scientific purposes, with subsidiary seconds at 6 o'clock. Silver colour dial, with large suspended Arabic numerals; blued steel “Spade” hands.


LOADING IMAGES
Click to full view Click to full view Click to full view
Image Image Image
Grading System
Grade:
Case: 3-8

Good

Slightly scratched
Movement: 3*

Good

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

Good

HANDS Original

Brand Patek Philippe, Switzerland

Model pocket chronometer, so-called “Deck-Watch”

Reference 738

Year Made in 1929

Movement No. 193434

Case No. 625957

Diameter 60 mm.

Caliber 19’’’ movement, rhodium-plated, going barrel, straight-line lever escapement, cut bimetallic compensated Guillaume balance with gold poising screws and blued steel hairspring with terminal curve, polished steel index-regulator with swan-neck spring and micrometric screw, adjusted by the precision timer “régleur Francois Modoux'', Geneva, “Poinçon de Genève” (Geneva Quality Hallmark or Geneva seal) stamped twice.

Signature Dial, case and movement

Accessories Extract from the Archives and extract from the chronometer archives

Notes

“Deck-Watch”

A “deck-watch” is a precision watch used on the deck of boats for navigational purposes (point reading) to avoid disturbing the proper functioning of the marine chronometer, which remains in a specific area of the ship (chronometer room or captain’s cabin).

For more information on this type of time-keeper, now a collector’s item, see Norbert Eder’s reference book.

Bibliography
· Eder, Norbert, Beobachtungsuhren, Deck Watches und Chronomètres de bord, Munich, Callwey Verlag, 1987 (216 pp.; similar watch on the cover).

Guillaume Balance

The Guillaume balance is a compensated bimetallic balance, made of anibal (an alloy of steel and nickel) and brass, after the works of Dr. Charles-Edouard Guillaume (1861-1938), with which the middle-temperature error is practically eliminated.

The middle-temperature error (or Dent’s anomaly), is the difference between the rate of a chronometer at the mean temperature and the average of the rates at extreme temperatures.

This type of balance was used by the horological manufactories since 1904.


Real scarcity of real chronometers

By the end of the 19th century, the Swiss watch industry produced millions of watches. Each year, an infinitesimal part of them are especially manufactured and adjusted to be presented to the annual chronometrical contests of the observatories of Geneva or Neuchâtel.

With the improvement of production techniques, the observatory regularly reinforces the rules of the contest; this competition becomes, every year, always more difficult. On the very small quantity of watches subjected to the rigorous and impartial control of the observatories, a good part is rejected; only the best pieces remain in the running.

Winning a Bulletin de marche – especially one of “First Class” – allows watch manufacturers to prove their chronometry skills. The same applies to the distinctions obtained at industrial or artistic exhibitions, whether at regional, national or universal level. At a time when marketing and advertising do not exist, this is the only real way to promote a company to the public and potential customers.