Breguet marks the start of a new era for its

BREGUET MARINE

ÉQUATION MARCHANTE 5887

The house of Breguet marks the start of a new era for its contemporary Marine Collection

Throughout his career, horologist Abraham-Louis Breguet consistently demonstrated his exceptional mastery of time measurement. His strong involvement and his revolutionary developments earned him significant recognition and numerous honours. Renowned the length and breadth of Europe, Breguet found a particularly active admirer in Louis XVIII, king of France. In 1814, the latter appointed him a member of the Bureau des longitudes in Paris. This body created in 1795 by the National Convention was dedicated to the advancement of the various branches of astronomy and their applications to geography, navigation, and geodesy (the measurement and understanding of Earth’s physical properties). Its tasks included the annual publication of reference documents such as astronomical ephemerides. The Bureau des longitudes was a prestigious organisation whose 20 or so members included geometers, astronomers, seafarers, and associate artists. The only representative of his profession that was eminently useful to physicists and navigators, Breguet became the horological authority, notably for the calculation of longitudes at sea. As an extension of this distinction, through an ordinance issued on October 27th 1815, Louis XVIII awarded A.-L. Breguet the official title of chronometer maker to the French Royal Navy.

This was the most prestigious title a horologist could hope to receive, given that the very concept of marine chronometry implied scientific knowledge. It also involved playing a crucial role for the country, as marine chronometers were of capital importance for fleets by making it possible to calculate ships’ positions at sea.

Following in the wake of this unique heritage, the House of Breguet now launches a worldwide exclusive model named the Marine Équation Marchante 5887. This “Grande Complication” marks the start of a new era for the contemporary Marine collection.

The equation of time is one of the rarest and most fascinating horological complications. It serves to display the difference between mean solar time, corresponding to civil or standard hours and minutes, and true solar time, meaning the actual solar hours and minutes.

Since Antiquity, the sun has been used as the basis of time. Nonetheless, the visible motion of the sun – the true solar time indicated on sundials – is irregular. With the improvement of timekeeping precision, watches and clocks became the basis of time and true solar time was replaced by mean solar time, within which each day has the same duration of exactly 24 hours. True solar time may show a discrepancy with mean solar time ranging from minus 14 minutes to plus 16 minutes.On just four days a year, the two times are exactly the same. Given that the variations between true solar time and mean solar time are repeated in an identical manner on the same dates, watchmakers can reproduce them mechanically by means of a special cam. Shaped like a bean, the cam requires extremely accurate execution. It is coupled with a feeler-spindle that drives an equation lever serving to indicate the difference between civil time and solar time. This read-off is generally provided on a sector or subdial. It is then up to the user to mentally add or subtract the difference displayed in relation to mean time in order to calculate true solar time.

The new Marine Équation Marchante from Breguet supersedes this principle. It simultaneously indicates civil time and true time by means of two separate minutes hands. The running solar hand, adorned with a facetted golden sun, provides a direct reading of solar time minutes that is both quicker and more user-friendly. This apparently simplicity conceals an arduous construction process that few watchmakers can achieve. The solar minutes hand must meet two imperative demands: it must sweep in a conventional way around the dial, like the civil minutes hand, while also daily moving away from the latter, to display true solar time considering the equation of time. Breguet was able to accomplish this by equipping its running solar hand with a differential gear powered by two rotation sources operating entirely independently: the rotation of civil minutes, and that controlled by the lever in contact with the equation of time cam, which makes one full turn per year. Breguet has developed an extremely slim equation cam borne by using a transparent sapphire disc.

The complexity that the running equation of time brings to this model is naturally complemented on this “Grande Complication” by a perpetual calendar. Two apertures – one between 10 and 11 o’clock and the other between 1 and 2 o’clock – respectively display the days of the week as well as the months and the leapyear cycle. The date appears inside the chapter ring by means of a retrograde hand tipped with an anchor motif and sweeping across an arc running from 9 to 3 o’clock.

The dial layout of the information has been carefully designed to ensure simple and intuitive linear reading, along with impeccable visual appeal. Based on the self-winding calibre, the new Marine Équation Marchante also flaunts a third complication that is noteworthy in its own right: a 60-second tourbillon with a titanium carriage housing a Breguet balance with a silicon balance spring.

This innovative characteristic notably enables the balance wheel to achieve a 4Hz frequency, while maintaining a particularly comfortable power reserve for a self-winding model.

This 80-hour autonomy is displayed through an aperture between 7 and 9 o’clock.

The tourbillon appears through the sapphire disc bearing the equation of time cam, to which it is coaxial. The ingenuity of this spectacular model is accentuated by the precious expertise of the artisans exercising their skills within the House of Breguet.

The front dial features two types of engine-turning, including a “wave” pattern specifically developed for this new creation. The inscription “Marine royale” is engraved on the tourbillon bar, whose execution naturally draws the gaze.

Visible through a sapphire caseback, the bridges have been delicately chased to depict in meticulous detail the Royal Louis, a first rank vessel in the French Royal Navy. The barrel is adorned with a windrose motif, in reference to astronomical navigation. With the positioning of the oscillating weight on the rim of the caliber, the self-winding movement deploys the full splendour of its decoration.