Echappement naturel

The ébauche was made by Bérare and delivered on 9 June 1802 to Breguet's design. The case was made by Pierre-Benjamin Tavernier and delivered on 12 August 1802. Charles Bernaudat made the first attempt at the escapement and delivered it in March 1803. Bernaudat altered some aspect of the escapement in April 1804 involving a stone in the escapement, either the locking pallet on the detent or the impulse pallet on the balance. Then Bernaudat made two final alterations to the escapement in September and December 1805. The payments for this work on the escapement, totalling about 1900 Francs (although this includes a payment for 'repassage', probably about 300 Fr) should be compared with the sale price at the time of one of Breguet's gold repeaters, about 1500 Francs. The work on the escapement in December 1805 was presumably the final modification since the watch was delivered to the Duke of Infantado in January 1806 for the price of 4000 Francs and the Breguet firm did not see the watch again for 32 years.

This was the first example of the échappement naturel and was constructed with the escapement on a detachable platform. Breguet used this arrangement in many of his marine chronometers so that his best escapement makers could perform the delicate construction and adjustments more easily. For this watch, the two escape wheels were of the same size, each having 10 impulse teeth arranged as pegs standing up from the rims of the wheels.

In contrast with the drawn out construction of 1135, this watch was produced quite quickly. The ébauche was made by Benoit and delivered in November 1804, Tavernier supplied the case in December 1804, Kehlhoff the escapement on 26 December 1804 and its repassage was completed by Bernaudat on 12 Feb 1805. There was now a delay of several months during which the final work was done on the dial and hands before being delivered to the buyer M. Galakoff on 5 September 1805 for the price of 3360 Francs. Mr. Galakoff had some problems with it, there were a couple of jobs done to it in the first few weeks, for example a new front crystal. Breguet bought the watch back from Mr. Galakoff in May 1806, had Tavernier engine-turn the back and re-numbered it as 2099 before selling it to M. Castaneda, an agent for the Spanish royal family, on 14 June 1806. The dates of the changes to the escapement of watch 1135 and the dates of construction of the escapement for watch 1711 overlap. It is therefore possible that lessons learned from the construction of watch 1135 were incorporated in 1711 and perhaps vice versa. In this watch the driven escape wheel was smaller, presumably because Breguet had come to the view that this was beneficial. George Daniels[1] pointed out that this reduction of the size and inertia of the driven wheel resulted in improved escapement performance. It was obviously not thought at the time to be beneficial enough to delay 1135 and redesign its escapement and train although the final escapement work was done after that of 1711. In this watch the driving escape wheel had 5 impulse teeth and the driven had 4. This was a relatively minor development from the design used in watch 1135.

The ébauche for this watch was originally supplied by Bérare in April 1802, a date consistent with its number. It then lay unused until Lapieur started construction of an échappement naturel in April 1805, completing it at the end of February 1806. It was cased by Tavernier by 8 April 1806 and Sagedieu performed the repassage between the end of May and mid-September of that year. The last entry in the workshop records is for 21 October 1806 when a minute hand was supplied but then it lay in the shop until consigned to its buyer Mr. Fenier of Moscow on 16 May 1808 for the price of 2640 Francs. The watch was re-purchased from Wenham, one of Breguet's agents, some time prior to 1821 and it was re-numbered as 2995 and traded (‘troc pour troc dire 3600 Francs’) for watch 1485 from a Mr. Rowse on 18 August 1821. Mr. Rowse was notionally allowed 3000 Francs for his watch, more than its sale price in 1806. In this watch the driving escape wheel had 8 impulse teeth and the driven had 4. The detent locking was also mounted on springs for the first time in order to protect against the escapement locking when the mainspring was run down.

The last of the four watches, 1484, does not now possess an échappement naturel but a double-wheel Robin escapement, a hybrid of the lever escapement and the chronometer escapement. Work started on the watch prior to September 1803. Sagedieu worked on an unspecified escapement between 10 February and 27 July 1804. Not much happened to the watch for six months except some jewel holes from Hooker, Breguet's jewel specialist brought from London. Lapieur then worked on an échappement naturel between the end of January and early May 1806. From the position of the original pivot hole for the second escape wheel, the two escape wheels appear to have had a 2:1 ratio of their size. The most likely tooth counts appear to be 8:4, the same as Lapieur made earlier for watch 1085 above. The watch was cased by Tavernier in June and Herault completed the repassage in August. In November 1806, Bernaudat was paid 300 Francs for 'ouvrage et visitage'. This considerable sum could have been for the removal of the échappement naturel and the construction of its current coaxial double-wheel Robin escapement. Nothing much happened again until mid-October 1808 when Bernaudat was paid another 60 Fr for changes to the escapement. At some stage the stop-work was replaced in a new sink in the barrel cap with a standard Geneva variety rather than Breguet's own design. No more work was done on the watch and another year and a half passed before it was sold to General Labadie on 28 Mar 1810 for the price of 1800 Francs.

Breguet used Robin escapements in a number of carriage and chamber clocks, at least one marine chronometer and more than a dozen watches between 1807 and 1823, mostly between 1807 and 1815. The series included a group of consecutively numbered minute repeating perpetuelles delivered between 1812 and 1816 and at least one tourbillon, number 1297 delivered in 1808. As Daniels[1] pointed out, the double lift Robin escapement suffered from a serious fault as a precision escapement. The necessity for oil on the lever impulse surface resulted in oil being transferred, via the escape wheel teeth, to the direct impulse pin on the balance for the alternative impulse. Some watches and carriage clocks had two separate coaxial escape wheels to keep the oil away from the balance impulse (as in 2179) but the Robin escapement was not apparently developed further after the échappement naturel for serious precision timekeeping in watches, except by Daniels himself in making the crucial developments that totally separate the functions of impulse and locking now used by Omega in his coaxial escapement.

A fifth watch could have been made during the development period for the échappement naturel. Watch number 2179 is a gold repeating watch of ‘normal’ size and is described on a Breguet certificate from 1971 as having an échappement naturel . However, it was catalogued for a sale in 2002 of items from the Time Museum by Anthony Randall as having a double lift Robin escapement. It is quite probable that work was started on this watch with a view to it having an échappement naturel but, like watch 1484, it was completed and taken into stock with a Robin escapement. Photocopies of the workbook entry accompanying the sale of the watch stated that its construction was started in 1806, after the delivery of both watch 1135 and watch 1711. It was sold on 29 December 1823 to the Duchess of Dalmatia for the price of 3200 Francs.

In the period 1808-1822 almost all watches using the échappement naturel were constructed on 4-minute tourbillon carriages, with 12+3 escape teeth, reversed fusees and sprung detent locking and were made to a similar pattern. The watches were large, typically 60-65mm in diameter and a distinguishing feature was their dials. These nearly all had a short hour hand indicating on a small central chapter ring and a large minute hand with a minute ring at the edge of the dial, see watches 1187 and 1188 in Daniels.[1] It is possible that the low price for the watch for the Bishop of Cambrai was because of their personal friendship. Judging by the rather modest mark-up of ~25% that Breguet applied to his workshop costs for other watches with this escapement, he might even have made a loss in this case. Breguet sold the Bishop another tourbillon watch, number 2436, for the same price but this one had a constant force escapement. During the period in which these watches were being sold (1808–1821), a few dozen tourbillon watches were being produced, about half with a lever escapement on a 1-minute carriage and the rest with a variety of escapements, a detent escapement on a 6-minute or 4-minute carriage, a couple with a constant force escapement and at least one with a Robin escapement. The sale of watches with tourbillon movements ceased after Breguet's death in 1823.