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Hotel Nogalhilton Geneve, Nov 11, 2001

LOT 298

Albert H. Potter & Co. Geneva, No. 9, made circa 1875.Exceptionally fine and rare 18K gold hunting cased keyless pocket chronometer.

CHF 30,000 - 40,000

USD 19,000 - 25,000

Sold: CHF 62,100

C. Four-body, solid, "bassine et filets" polished, five-link hinges, gold glazed cuvette. D. White enamel with radial Roman numerals, outer minute ring, sunk subsidiary seconds, snap-on fit. Blued steel Breguet hands. M. 20''', nickel, patented caliber, "fausses côtes" decoration, 22 jewels, most in gold screwed settings, patented pivoted detent escapement, counterpoised detent with shock-absorbing loop acting on adjustable eccentric gold screw with ruby cylindrical insert, gold passing spring,wo-armed cut bimetallic balance with gold temperature screws and large platinum quarter screws, blued steel free-sprung helical balance spring with terminal curves, patented motor barrel, lever-set.Signed on the dial and movement, case punched with Potter's trademark.Diam. 56 mm.


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Grading System
Grade:
Case: 3

Good
Movement: 2*

Very good

Overhaul recommended, at buyer's expense
Dial: 2 - 01

Notes

With its very unusual ruby shock-absorbing device, the present chronometer is one of the best Potter made. The watch employs a number of Potter's patents, the details of which are engraved on the bridges. The plate design was patented on January 4, 1876 (American patent No. 8888); the escapement (patent No. 168582), the motor barrel (patent No. 168581) and the balance (patent No. 168583), on October 11, 1875.Albert Potter's work is always of top quality and offers completely original solutions to mechanical problems. For instance, the energy loss which occurs during unlocking is less dependent on the state of winding and consequently the balance amplitude change is smaller and the degree of isochronism greater. The unlocking angle is smaller, reducing the risk of setting. The banking pin, which allows the tail of the detent to act as a shock-absorber is most unusual. Its ruby insert reduces frictionwhen a shock occurs. The elaborate barrel design reduces the risk of damage to the train in case of mainspring breakage. An identical watch (but with later brass case and without shock-absorber ) is in the collection of the British Museum, No. CAI -1834.