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THE POTTER CHRONOMETER

Details
THE POTTER CHRONOMETER

AN AMERICAN EIGHT-DAY MARINE CHRONOMETER OF EXCEPTIONAL QUALITY AND CONSTRUCTION WITH "PIVOTED" DETENT
Albert H. Potter, unumbered, circa 1880

the silvered? dial signed Made by Albert H. Potter For W.W. Griscom, Roman hour numerals, gold hour and minute hands, subsidiary seconds and up-and-down dials with blued steel hands, all movement plates, potance and balance cock satin gilded, jewelled to the centre with screwed chatons, the main frame assembly inscribed ALBERT H. POTTER & CO. Escapement Pat Oct. 11 1875 carrying barrel fusee (reversed) and centre wheel, sub-frame assembly inscribed Balance Pat. 11.75 carrying chain protector remainder of train and Earnshaw escape, Potter patent cut bimetallic balance of complex construction carrying two semi-circular bimetallic auxiliaries each with adjustable radical screws, blued steel helical balance spring with terminal curves, Potter's patent pivoted detent (Patent Nos. 168 582 of 11 October 1975), brass bowl, gimballed in brass-bound mahogany box, plain bone ivory disc to centre section, flush inset brass handles
118mm. dial diam., 206mm. sq. box
Provenance
W.W. Griscom and by family descent, bought from his neice by the present owner.
Literature
Whitney, Marvin, The Sea Chronometer.

Lot Essay

Born in 1836 in Mechanicville, New York, Albert H. Potter was in 1852 apprenticed to Wood & Foley, watchmakers, of Albany. In 1855 he went to New York City where he opened a watch repairing workshop at 19 John Street, subsequently moving to 84 Nassau Street where he began designing and manufacturing watches. The quality of his work was of a very high standard and, because of this, he could command high prices.
In 1861 he moved from New York to Havana and opened yet another successful horological business. Returning to America in 1866 he settled in Williamsburg, New York where he worked on the designs and construction of different escapements. One of these was a chronometer escapement for which he was granted Patent No. 736646 dated 21 January 1868. Shortly after this he moved to Minneapolis, moving again in 1870 this time to Chicago and in 1872 he entered into partnership with his brother William Cleveland Potter. The partnership was dissolved in 1875. Shortly after this he left America for Switzerland.

He set up business in Geneva, a city which he loved and where he died 25 January 1908.

However, before leaving America he applied for two horological Patents viz No. 168,582 for an "Escapement for Watches" and No. 168,583 for a "Compensation Balance for Watches". Both were granted on 11 October 1875.

Patent No. 168,582 describes and illustrates a pivoted detent chronometer escapement and it was only when the chronometer was recently fully examined that it was discovered that this marine chronometer escapement and detent conformed to the Patent specification, where also its shape and action, particularly that of the passing spring assembly, is explained. The detent has a very small spiral hairspring fitted to its arbor which is the return sprin. Banking of the detent is achieved by the outer end being in the shape of a shepherd's crook (or question mark) - see Fig. 1 in the specification; the top plate of the sub-frame assembly carrying the escapement has round hole in it, the diameter of which is slightly larger than the outside diameter of the counterweight and into which the counterweight fits and which controls the lateral movement of the detent.

Patent No. 168,583 describes the construction and principles on which it functions of a compensation-balance for watches. The balance fitted to this chronometer appears to be based in gneral principles and theories explained in the Patent specifications but is, in fact, of a more refined and complex design and construction.

What is without doubt is that the quality of horological craftsmanship in the detent, and in particular the balance, is of the very highest.

A pocket chronometer by Potter is in the British Museum collection and the action and design of his pivoted escapement is given in the Catalogue of Watches VI, entry 30, page 56 and Plates 24(e) and 25(a).
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