Last updated on August 5, 2022
(A collector alerted me, unfortunately too late, about this clock for auction. It was signed on the movement by Henry Sully from his time heading up a manufacture at Saint-Germain en Laye. It sold on 2 March 2022 for 1,700 GBP, to a bidder in the room (there were only two bids on the clock, surprisingly). I regret not having had an opportunity to bid on this item, which would have been an important acquisition for my research on Sully’s life and works. Also in the sale, from the same original owner, were four editions of Sully’s “Règle Artificielle du Temps” (including one in German). Following is the detailed description and few photographs put up by the auction house – Dreweatts in the UK. There are a few inaccuracies in their text, which I have corrected with notes in [square brackets].
A RARE FRENCH LOUIS XV BOULLE BRACKET TIMEPIECE
HENRY SULLY, SAINT GERMAIN EN LAYE, CIRCA 1725 
The single going barrel movement with tic-tac escapement regulated by disc bob pendulum and rectangular plates incorporating canted lower angle united by four baluster pillars pinned at the rear, the backplate engraved Sully a St. Germain en Laye above the external mainspring barrel click, the 6 inch circular gilt brass twelve-piece enamel Roman numeral cartouche dial with Ho-Ho bird and lambrequin inhabited scroll-decorated centre within blue-on-white Roman hour numerals within rococo borders and with every minute numbered to outer track, with sculpted blued steel hands the engraved cut brass and brown shell marquetry decorated case with seated martial putto surmount to the domed caddy superstructure veneered with leafy scroll decoration and applied with foliate mounts to angles over swan neck centred crest flanked by rosettes, the front with brass-framed arched glazed door enclosing marquetry decorated ’tiled; floor and contra-parti veneered back panel to interior and incorporating cast panel featuring Ho-Ho birds grappling to apron, the surround decorated with leafy scrolls within line edging, the sides with scroll inlaid outswept upper sections terminating in batons applied with gilt swags over brass-edged windows with canted upper angles and arched lower rail over further laurel cast mounts to inlaid lower margins, on feet cast as dolphins with foliate scroll decorated apron between, (the movement previously with silent-pull repeat mechanism).
58.5cm (23ins) high, 28cm (11ins) wide, 16.5cm (6.5ins) wide.
Henry Sully was born in 1680 and was apprenticed to Charles Gretton gaining his Freedom of the Clockmaker’s Company in 1705. After a short period working as a journeyman for his former Master he left for Continental Europe first to Leiden 1708-11 then to Frankfurt and Vienna before settling in Paris in 1715. Whilst in Vienna he published his first book ‘Regle Artificielle du Temps’ in 1714 with the first French version  subsequently published in Paris in 1717. It was at this time he formed a close working relationship with Pierre LeRoy  and presented his first ‘Montre de Mer’  to the Academie des Sciences in 1716. In 1718 he established a watchmaking factory at Versailles before setting-up another in Saint Germain en Laye in around 1724 . During his time in St. Germain Sully continued developing his designs for a Longitude timekeeper  and in 1726 one of his timepieces (utilising his modified version of Debaufre’s escapement with two diamond pallets) was trialled off Bordeaux. Henry Sully unfortunately died in 1728 bringing his efforts to further develop his Longitude timekeeper to an abrupt halt; if he had lived longer it is possible that he could have devised an appropriate timepiece well in advance of Harrison’s ‘H4’ of 1759 .
Surviving clocks and watches by Henry Sully are very rare; the current lot is probably the only ‘domestic’ timepiece by him to survive from his time at St. Germain en Laye.
PLEASE NOTE description updated to confirm that the movement has a tic-tac escapement rather than a verge escapement 25/02/2022.
Please note that the present clock has a tic-tac escapement not verge as indicated in the printed catalogue. The going train appears all-original and is in relatively clean working condition. The backcock is now fitted with a suspension spring for the pendulum – originally it would have had a silk thread. Spare holes in the plates indicate that the movement was most likely originally fitted with pull-quarter repeat work which has now been removed. The dial is generally in good original condition with visible damage limited to hairline cracks across the X and II numerals. Many of the cartouches have now been secured to the dial plate with solder applied from behind. The hands appear original and are very nicely sculpted.
The case is generally in very good original condition exhibiting rich but mellow colour to the gilt mounts and brass marquetry. The veneers are in very good original stable condition with minimal lifting and only a few very small losses to the brass. The superstructure has had the joints reglued otherwise faults to the case are generally limited to very slight bumps, scuff, shrinkage and wear commensurate with age and use.
The clock has a pendulum but no case key or winder.
 As note 4 below attests, the date of the clock was not 1725, but rather 1720 or 1721.
 All editions of Règle artificielle du temps were written in French.
 It was actually Julien Le Roy with whom Sully formed a lengthy partnership, and friendship. However he likely also knew Julien’s younger brother Pierre-François, also working as a “horloger” in Paris at the time.
 It was referred to as “Montre pour la mer” (watch for the sea) and this machine was numbered 177 by the Académie in its records.
 The factory at Versailles was created by financier John Law, with Sully hiring London workers and leading things, sometime in 1719. A year later, in 1720, John Law dismissed Sully as its Director, replacing him with James Reith, the assistant Director. After spending some months lamenting his loss of status and employment, Sully proposed successfully to the Duke of Noailles to setup a separate horological factory, in St-Germain en Laye. This factory started operating sometime in late 1720 and competed with the one in Versailles. By late 1721, both factories were forced to close, largely due to difficult economic conditions in France (which forced John Law to flee the country), diminishing the demand for such horological products.
 In fact, Sully resumed his work on a marine timekeeper when he was forced to briefly return to London in 1721, after the closure of the St-Germain en Laye factory. He continued this work when he subsequently returned to Versailles, sometime in 1722, where he earned a simple living repairing watches, having lost whatever small savings he may have earned while briefly heading up both horological factories.
 It is pure conjecture to suggest that, had he lived, Sully may have successfully developed a reliable marine timekeeper ahead of Harrison’s H4, but one will never know. One thing is certain: some of the technological discoveries needed to produce a reliable marine watch (detent escapement, bimetallic balance compensation for temperature changes, etc.) would have to wait for Pierre Le Roy’s work some decades after Sully’s death, and subsequent work by Ferdinand Berthoud.
The photos below of the Sully clock, are from the online ad by Dreweatts in preparation for their sale on 2 March 2022. More detailed photos were not to be had. Perhaps the person who acquired the clock will one day document his/her acquisition so all people interested in Henry Sully can learn from it.