With Breguet Certificate no. 4367 dated 23 March 2012.
Sold on 10 January 1827 to Peyronnet, Banquier in Paris, for the amount of 7'500 francs; taken back; resold on 3 November 1834, to the Count Charles de l'Espine for the amount of 8'000 francs (at this time with the certificate no. 1061).
This remarkable watch possesses an ingenious and simple equation of time mechanism, which interferes only minimally with the going train. The equation mechanism engages with the motion work only once every 2 hours, and then briefly, minimalizing the resistance on the train. To achieve this Breguet designed a mechanism whereby the motion is transmitted from the mean time motion work to that of the solar time via a double spring-loaded wheel joined together by a system of two pivoted racks and a pinion. One rack advances the bottom wheel, the other retreats. This is done by a lever controlled by the equation cam mounted on the annual wheel. When the lever closes in, the small dart mounted on the advancing rack pushes the rack, which advances the pinion on the intermediate motion wheel, which in turn transmits the difference to the solar motion work. When the lever retreats, the mechanism takes over and every two hours releases the click holding both wheels together. It retreats until the dart falls on the equation lever. Since the watch is built on the principles of the "garde temps", Breguet apparently wanted to make sure that the forces interfering with the isochronisms of his chronometer were kept to a minimum. The equation mechanism is driven from the days of the week wheel which turns once every five weeks. Its extension is fitted with a 20-leaf pinion driving the centre annual wheel which carries the equation cam. Another unique feature of the watch is its manual perpetual calendar. The owner needs only to engage the lever protruding through the band once every four years, and the calendar adjusts to the correct day. The watch is exceptionally well finished. Its entire going train is jewelled; the escapement has end-stones and is superbly finished. The combination steel and platinum balance, although not unknown in Breguet watches, is reserved for his best pieces. The pallet fork with equidistant pallets, two platinum counterpoised weights, and draw, is well ahead of its time; it became popular in the 1860's. The sunken centre of the bevelled and mirror-polished balance arm was specially made to assure that the watch be slim. Indeed, its slimness is remarkable for a watch with such complications.
The drawing of another equation of time watch was published by Professor Thomas Engel in his book A.L. Breguet, Watchmaker to Kings, 1994, p. 177.
The equation indications used by Breguet are fully explained and illustrated by George Daniels in his The Art of Breguet (1975), pp. 347-350, ill. 422, 423a-c.
Garde-temps is a term used by Breguet specifically to indicate high-precision watches. A true guarantee of quality, the term could be applied to pieces for scientific use as well as for civils (civilian), pieces such as this watch, made to the same principles as the garde-temps or chronomètres.
Breguet's equation of time watches
Among the fifteen equation of time watches (indicating the difference between the mean time and the real, solar, time) manufactured by Breguet and his son Antoine-Louis Breguet (1776-1858) between 1790 and 1830, certain, in particularly early examples, featured the sectorial indication, others the "running" variant. The present watch however is part of a series of only five watches with two independent dials allowing a much easier reading of the mean time and the real (or solar) time. Of these five pieces, only two are equipped with a repeating mechanism (striking upon demand) of the hours and half-quarters, such as this watch. The combination of these horological complications render these two watches the most complex timepieces of this type.
The workshop drawing and explanations (no. 1061) of the watch offered in this auction is reproduced thanks to the courtesy of Mr Emmanuel Breguet, director of the archives of Montres Breguet in Paris.
List of Breguet's equation of time watches with two dials:
No. 2807 (23''', with age and moon phases); case in gold
Sold on 26 August 1817, to Wilhelm I (1781-1864), King of Wurttemberg (1816-1864), for the sum of 4 800 francs (sent through Colonel Germain (Hermann) Baron von Wimpffen (1749-1820), former aide de camp of the deceased king); the watch had in fact been ordered by his father, Frederick Wilhelm I of Wurttemberg (1754-1816), Duke of Wurttemberg (1797-1803), under the name of Frederick III, Elector (1803), then King of Wurttemberg (1805-1816), but following the king's death, the money was reimbursed and the watch returned on 10 November 1817; it was then sold on 25 July 1818, to Alexis Petrovich Yermoloff (1772-1861), Russian general, for the sum of 4'000 francs.
Patek Philippe Museum, Geneva (Inv. S-870).
No. 3862 (25''', with age and moon phases); case in gold, the mid-1960s
Started between 1821 and 1824, completed between 1965 and 1968; sold on 25 October 1968 to Dr Halpern for the sum of 70'000 francs.
Collection Montres Breguet S.A., L'Abbaye, Vallée de Joux.
No. 3863 (25''', with age and moon phases and à tact hand); case no. 3937, in gold, by Tavernier
Sold on 17 August 1824 to Mr Granger for the sum of 5'200 francs (certificates no. 903 and no. 2926).
Royal Collection, Middle East.
No. 4111 (25''', with half-quarter repeating); case no 4072, in gold, by Tavernier
Sold on 10 January 1827 to Peyronnet for the sum of 7'500 francs; returned; sold on 3 November 1834 to Count Charles de l'Espine for the sum of 8'000 francs (certificate no. 1061).
The present watch.
No. 4112 (25''', with half-quarters repeating); case no. 4192, in gold, by Tavernier
Sold on 1 June 1829 to Mr Goding for the sum of 8 128 francs (£320.-) (certificate no. 1206).
At the end of the nineteenth and beginning of the twentieth century, The Sir David Lionel Salomons Collection, London (Inv. No. 12; certificate no. 2520).
Jerusalem, L.A. Mayer Memorial Institute for Islamic Art, The Sir David Lionel Salomons Collection (Inv. WA 98-71).
Equation of Time
First of all one must be reminded that to adjust their timepieces, watchmakers in the past had no alternative than using the true noon, meaning to determine when the sun is at its highest point. A convenient way of defining this is with a sundial. Existing in a variety of forms, they were used until the second half of the nineteenth century, when electricity took over. Today, the talking clock or the hourly chime announced on the radio allow us precise setting of a watch or clock, whether at day or at night.
The equation of time in astronomy is the quantity that needs to be added or subtracted to switch from real time given by the sun, to the mean time; our time, which arbitrarily divided a day in 24 hours. The equation of time varies from one day to another, its value swings between around -16 to +16 seconds per day. By cumulating these differences, we obtain a variation between the real noon and the mean noon of more or less 15 minutes. The most important differences are, function of the years, toward February 12 (+14 minutes and 59 seconds) and November 3 (-16 minutes and 15 seconds). The difference is zero toward April 15, June 15, September 1 and December 24. It should be known that today, due to the summer time and the winter time, we live with a difference of two or three hours relative to the sun; our daily noon corresponding to the solar noon of Central Europe.
The equation of time also gives information about the equinoxes of spring (21 - 22 March) and autumn (22 - 23 September), as well as the solstices of summer (toward 21 June 21) and winter (toward 21 December). The equinox is the moment when the sun is on the plane of the equator, thus leading to days equal to nights. The solstice is the moment when the sun is in the farthest position from the equator, resulting in the longest day and the longest night. These dates determine the seasons of the year.
Prior to 1600, Jobst Bürgi (1552-1632), Swiss watchmaker, astronomer and mathematician, built the first instruments and clocks showing the equation of time. Mechanic of the Margrave Wilhelm IV of Hesse-Cassel (1532-1592), watchmaker of the Emperor Rudolph II (1552-1612), then collaborator of Tycho Brahe (1546-1601) and Johannes Kepler (1571-1630) in Prague, he was a pioneer in many fields.
In 1657, after the invention of the pendulum by the Dutch scientist and mathematician Christiaan Huygens (1629-1695), clocks could be adjusted with a precision of a few seconds per day. The question of the difference between the solar time and the mean time was then asked. Scientists such as Huyghens or John Flamsteed (1646-1719) authored tables showing the equation of time. Sundials with the equation were created, especially by the London-based clockmaker Thomas Tompion (1639-1713).
It is commonly accepted that the oldest equation clock - indicating simultaneously the mean time and the real time - was imagined by Nicholas Mercator (1640-1687), English mathematician and member of the Royal Society of London; Ahasuerus Fromanteel (1607-1693), London-based watchmaker of Flemish origin, manufactured the clock towards 1666 under Mercator's guidance.
Soon after, other scientists and watchmakers of the time started manufacturing them as well. From England we recall the names of Dr. Robert Hooke (1635-1703) and Thomas Tompion, followed by his successors Daniel Quare (1649-1724) and George Graham (1673-1751). On the continent, at the turn of the seventeenth and eighteenth centuries, other scientists and watchmakers were hard at work: the Abbot Jean de Hautefeuille (1647-1724), Hans Georg Enderlin of Basle (1678-1754), Henri Sully (1680-1729), Julien Le Roy (1686-1759), Dom Jacques Alexandre (1653-1734), Charles Le Bon (born on 1678) and Antoine Thiout (towards 1694-1761).
The middle of the "Siècle des Lumières" or the age of enlightenment was marked by the invention of the meridian helping to determine the real noon with the naked eye. Then the mean time meridian was created. It is a curve shaped like an elongated "8", divided in two by a line thanks to which the mean noon is calculated. In Geneva, the astronomer Jacques-André Mallet (1740-1790) calculated the one placed on one of the walls of the Saint-Pierre Cathedral. Moved during the Swiss National Exhibition of Geneva in 1896, it can now be found on the Southern side of the Tour de l'Ile, above the statue of Philibert Berthelier (around 1465-1519), fervent defender of liberty in Geneva.
During the second half of the eighteenth and the first half of the nineteenth century watches with equation of time appeared. Some of the greatest watchmakers of the period manufactured clocks, pendulums and watches: Ferdinand Berthoud (1727-1807), the Frères Lepaute, Jean-André (1720-1789) and Jean-Baptiste (1727-1802), Jean-Antoine Lépine (1720-1814), Robert Robin (1742-1799), Abraham-Louis Breguet (1747-1823), Louis Berthoud (1754-1813), Charles Oudin (1768-1840), Nicolas-Mathieu Rieussec (1781-1852), Jacques-François Houdin (1783-1860), Henri Robert (1795-1874) and Louis-Constantin Detouche (1810-1889). In Great Britain, John Ellicott (1706-1772), Thomas Mudge (1715-1794) and Edward John Dent (1790-1853) were also involved in the field. In the Principauté de Neuchâtel (Switzerland today), Samuel Roy (1746-1822) and his sons manufactured them as well.
During the second half of the nineteenth century, most of the equation watches are created or sold by the most prestigious watch making workshops and brands in the Valle de Joux and Geneva: Louis Audemars (founded in 1811), Audemars Piguet (founded in 1875), Victorin Piguet (founded in 1880), Vacheron Constantin (founded in 1755) and Patek Philippe (founded in 1839).