Albert H. Potter & Co., Geneva, Movement No. 65, 55 mm, 169 g, circa 1880
An important precision hunting case pocket watch with Potter's patented pivoted detent chronometer escapement
Case: 18k gold, tiered, polished, signed, à goutte, glazed movement. Dial: enamel, radial Roman hours, auxiliary seconds, signed, blued Breguet hands. Movm.: specially designed bridge movement, nickel-plated, decorated, screwed gold chatons, "Escapement Pat. Oct. 11.75", "Plate desn Pat. Jan. 4.76.", special form pivoted detent chronometer escapement, heavy compensation balance with gold and platinum screws, freesprung blued helical balance spring, gold escape wheel.
Albert H. Potter pivoted detent chronometer
The present watch is an excellent example of the very highly finished pivoted detent chronometer calibre created by Albert H. Potter; Potter was and remains probably the most celebrated American maker of pocket chronometers. In the latter part of his life he worked in Geneva, where he was able to find accomplished craftsmen to work with him. This watch features a number of peculiarities which are typical for the work of Albert Potter. It has his patented safety barrel (patent No. 168581) to protect the going train from the effects of mainspring breakage; it uses a considerable amount of height, which means that the spring is unusually narrow for such a large watch. The pivoted detent escapement has Potter's own design of pivoted detent with a special arrangement for the spring intended to make the passing action as smooth as possible; a circular counterpoising tail is carried on a piece at right angles to the blade near the free-end of the detent. A single pin set in the end of the escape wheel cock provides banking for the detent. Therefore no adjustment for the depth of locking is needed. This arrangement of the passing spring on an outrigger on the end of the detent was used earlier by James Ferguson Cole. The elegant plate design of this calibre allows for easy setting of the train and was patented on April 5, 1887. The mechanism for winding and setting is unique for Potter, although he did not patent this particular design: its intermediate setting wheel moves vertically for engagement, the click pin protruding by the barrel affords an easy and secure means of letting the spring off, and Potter’s typical glazed cuvette allows the movement to be seen. There are very small discrepancies between Potter’s early chronometers and the later ones; early ones have spotted movements while the later ones are usually decorated with Geneva stripes and were almost always stamped with Potter's large trademark, unlike the early ones. Kalish mentions that Potter used to say he had no need to stamp his cases, since everyone recognized his work anyway. Early pieces have a traditional balance spring stud, the later ones are far more elegant. This watch uses several of Potter's patents and has their details 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 also always of the highest quality and with completely original designs.
机蕊 非常好, 走動正常
机蕊 非常好, 走動正常