.jpg?w=1)
.jpg?w=1)
.jpg?w=1)
.jpg?w=1)
拍品专文
This remarkable and exceptionally rare complicated watch by the great Abraham-Louis Breguet demonstrates admirably his unique ability to design and make watches that were ingenious in demonstrating new solutions in the development and manufacture of watches with highly complicated functions. As such, the present watch, displaying indications for both the Gregorian and Julian calendars, equation of time, zodiac and days of the week, is a significant historic masterpiece and a true prize for the serious collector.
Furthermore, it was chosen by Emmanuel Breguet to be prominently illustrated in: ‘Breguet, Watchmakers Since 1775’, pp. 164, 172, 173.
Although recorded in the Breguet Archives as being sold in August 1805, it is possible to date the manufacture of this watch even more accurately due to the reverse of the dial being signed by the dial maker Borel and dated ‘Fructidor an 11’ - showing that it was likely being finished in the second half of 1803. It uses Breguet’s own equation of time system, the design of which was also employed in the double pendulum resonance clock No. 3671 sold to King George IV in 1825.
Breguet had been making watches with equation of time function as early as the 1790s with the ‘cam’ type equation mechanism. However, the present watch represents an alternative to the traditional equation of time mechanism, it is an ingenious system which engages with the motion work only briefly, once per hour, therefore placing almost no additional resistance on the going train. The equation mechanism itself is driven from the hour wheel 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 makes it retreat. This is done by a lever controlled by the equation cam mounted on the annular 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 simple mechanism takes over and every hour releases the click holding both racks retreating until the dart falls on the equation lever.
In addition to the present watch, three other examples of Breguet’s watches fitted with this particular type of equation of time system are known:
- No. 3807: whereabouts unknown
- No. 3862: sold at Christie's Geneva on 18 May 2004, lot 240, for CHF482,400. Formerly in the Time Museum, Inv. No. 578
- No. 3863: illustrated in : ‘The Art of Breguet’, George Daniels, p. 261
The present watch, No. 1348, is the earliest known example.
As well as displaying equation of time, Breguet No. 1348 also displays indications for both the Gregorian and Julian calendars. This is facilitated by another ingenious yet simple device: placed at 90 degrees upon the tip of the steel calendar hand is a gold pointer, whilst the tip of the steel hand indicates the date using the Gregorian calendar, the date in the Julian calendar can be determined by reading off the date shown by the end point of the gold pointer. For example: if the steel hand shows a date of 21 August, the gold pointer indicates the 9 August – a 12 day difference in calendar dates that was correct in the period the watch was made.
Equation of Time
For a watch with an equation mechanism, an indication of the date is always required because the equation varies continuously throughout the year. This information is useful when setting a watch to time given by a sundial. By adding or subtracting the equation for the day, as indicated by the hand, the sundial time could be corrected to mean time.
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 minutes 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. 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.
The equation indications used by Breguet are fully explained and illustrated by George Daniels in: 'The Art of Breguet' (1975), pp. 347-350, ill. 422, 423a-c.
Furthermore, it was chosen by Emmanuel Breguet to be prominently illustrated in: ‘Breguet, Watchmakers Since 1775’, pp. 164, 172, 173.
Although recorded in the Breguet Archives as being sold in August 1805, it is possible to date the manufacture of this watch even more accurately due to the reverse of the dial being signed by the dial maker Borel and dated ‘Fructidor an 11’ - showing that it was likely being finished in the second half of 1803. It uses Breguet’s own equation of time system, the design of which was also employed in the double pendulum resonance clock No. 3671 sold to King George IV in 1825.
Breguet had been making watches with equation of time function as early as the 1790s with the ‘cam’ type equation mechanism. However, the present watch represents an alternative to the traditional equation of time mechanism, it is an ingenious system which engages with the motion work only briefly, once per hour, therefore placing almost no additional resistance on the going train. The equation mechanism itself is driven from the hour wheel 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 makes it retreat. This is done by a lever controlled by the equation cam mounted on the annular 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 simple mechanism takes over and every hour releases the click holding both racks retreating until the dart falls on the equation lever.
In addition to the present watch, three other examples of Breguet’s watches fitted with this particular type of equation of time system are known:
- No. 3807: whereabouts unknown
- No. 3862: sold at Christie's Geneva on 18 May 2004, lot 240, for CHF482,400. Formerly in the Time Museum, Inv. No. 578
- No. 3863: illustrated in : ‘The Art of Breguet’, George Daniels, p. 261
The present watch, No. 1348, is the earliest known example.
As well as displaying equation of time, Breguet No. 1348 also displays indications for both the Gregorian and Julian calendars. This is facilitated by another ingenious yet simple device: placed at 90 degrees upon the tip of the steel calendar hand is a gold pointer, whilst the tip of the steel hand indicates the date using the Gregorian calendar, the date in the Julian calendar can be determined by reading off the date shown by the end point of the gold pointer. For example: if the steel hand shows a date of 21 August, the gold pointer indicates the 9 August – a 12 day difference in calendar dates that was correct in the period the watch was made.
Equation of Time
For a watch with an equation mechanism, an indication of the date is always required because the equation varies continuously throughout the year. This information is useful when setting a watch to time given by a sundial. By adding or subtracting the equation for the day, as indicated by the hand, the sundial time could be corrected to mean time.
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 minutes 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. 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.
The equation indications used by Breguet are fully explained and illustrated by George Daniels in: 'The Art of Breguet' (1975), pp. 347-350, ill. 422, 423a-c.