The Art of American Horology & Colle...

New York, Nov 28, 2001

LOT 183

Albert H. Potter & Co., Geneva, No. 74, made circa 1880.Exceptionally fine and rare, 18K gold hunting-cased keyless pocket chronometer.

USD 20,000 - 24,000

Sold: USD 23,000

C. four-body, massive, "bassine et filets" polished, five-link hinges, gold glazed cuvette. D. white enamel with Roman numerals, outer minute ring, sunk subsidiary seconds, snap-on fit. Blued-steel Breguet hands. M. 45 mm (20'''), nickel, patented caliber, "fausses côtes" decoration, 22 jewels, most in gold screwed settings, patented pivoted detent escapement, counterpoised detent, gold passing spring, two-armed cut-bimetallic balance with gold temperature screws and large platinum quarter screw, 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 trade mark registered on??.Diam. 56 mm.


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Grading System
Grade: AAA

Excellent
Case: 3

Good
Movement: 3*

Good

Overhaul recommended, at buyer's expense
Dial: 3-43-01

Good

HANDS Original

Notes

This 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. The same inventions were patented six weeks earlier in England under patent No. 2985 of Aug 25, 1875.Albert Potter's work is not only rare, but always of top quality, offering completely original designs. The energy loss of unlocking his escapement, for example, is less dependant on the state of winding. Consequently, the balance amplitude change is smaller and the degree of isochronism is greater. The unlocking angle is smaller, reducing the risk of setting. 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) is in the collection of the British Museum, No. CAI -1834. For two other exceptional Potter watches, see Prof. Thomas Engel Collection, Antiquorum, November 11, 2001, p.103-04.