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Auktionen Dr. Crott 88. Auktion

THE PERFECT MARINE BALANCE LONGITUDE CLOCK “BALANCIER MARIN PERFAIT” (BMP), circa 1685  This is the earliest known longitude timekeeper. Its historical and horolo- gical importance can be summarized by: – It is the earliest known longitude clock in existence – Its mechanics inspired Harrison and likely contributed to his 20,000 award from the English Board of Longitude for H41 – It is the only surviving Huygens longitude timepiece – It is the culmination of Huygens lifetime of experience – It is the earliest surviving clock with an attempt to create a frictional rest escapement – It is the earliest surviving equation of time clock – It is the earliest known clock employing disc bearings (anti-friction rollers) – It is the earliest or one of the earliest known continental clocks with maintaining power INTRODUCTION In modern horological literature, this clock is mentioned once and only briefly by John Leopold in his address at the 1993 Longitude Symposium at Harvard: “…in March 1695, Huygens had an existing clock (with equation of time) converted to the new balance, but about this we have no further details. … A publication on the new clock, which he had announced shortly before his death, was never written“.2 Leopold based his remarks on Huygens’ last surviving letter,3 written in March of 1695, in which Huygens writes to his only brother about converting an existing three-foot pendulum clock with equation of time to his new invention. Huygens employed two new concepts in this clock: his Perfect Marine Balance and a new form of escapement apparently also invented by him. The Perfect Marine Balance is an unusual union between a pendulum and a balance consisting of a large foliot (balance) with a small pendulum affixed to it. The concept sounds strange but, as Huygens proved mathe- matically, it is isochronous.4 The new escapement, invented by Huygens, is the first attempt to create a frictional rest escapement. The impulse is given to a chronometer-like pallet by one escape wheel with locking via the second wheel. KNOWN HISTORY OF THE BMP2 CLOCK Early 1680s - 1695. In the possession of Huygens. 1695-1754. In the Huygens family. 1754 Auctioned by Huygens family (Oeuvres Complètes de Christiaan Huygens, vol. 15, pp. 19-21). 1754-1980s Whereabouts unknown. 1980s-2002 Time Museum, Rockford, USA (Inv. 727). 2002 Auctioned at Sotheby‘s Time Museum Sale on June 19, lot 129, misattributed to Sully. CLOCK IN THE TIME MUSEUM The clock was purchased by the museum in the 1980s. It was an inexpensive purchase; the cost was $20,0005 . The clock did not work; the seller thinking that it supposed to have a pendulum, attached a mock short pendulum to one arm of the foliot via its cylindrical weight. The locking cylinder was slid to the impulse pallet. Who would have thought then that it was one of the most important clocks in the museums collection? ATTRIBUTABILITY TO HUYGENS – Only Huygens (later Sully) made Perfect Marine Balance clocks. The fact that the clock was meant for a Perfect Marine Balance is evident from the arrangement of the plates. The 4PthP and the 5PthP wheels are bridged to make extra space, a space that does not make sense for any other arrangement than Perfect Marine Balance. – Huygens wrote that he converted a pendulum clock to fit his new invention.6 This clock used to be fitted with a pendulum. There is clearly a slot for a pendulum as well as for the pendulum locking. – Huygens wrote that his clock had equation of time mechanism. This is the only such early clock with equation of time in existence. – Only Huygens and Sully made clocks with the Perfect Marine Balance. This clock was not made by Sully (see below). That leaves only Huygens. THE ISSUE OF PAST MISATTRIBUTION OF THE CLOCK With the dispersion of the Time Museum the clock was entrusted to Sotheby‘s to be auctioned. Sotheby’s in the June 19, 2002 catalog attri- buted the clock to Sully because “…the design of the movement of this complicated clock incorporating anti-friction rollers in the escapement suggests that it may have been made by Henry Sully“. Sotheby‘s apparently was under the impression that the friction rollers were used only by Sully. In fact, anti-friction rollers were invented and used way before Sully. They were well known to Huygens.7 They were even known to Leonardo da Vinci who drew them in 1494 (Codex Madrid I). Clearly, the attribution of the clock to Sully based on his supposed sole use of anti- friction rollers has no grounds. THE CONCEPTION OF THE BALANCIER MARIN PARFAIT (PERFECT MARINE BALANCE) After the failures with pendulum-based longitude clocks, Huygens put his efforts into devising a balance marine clock. Knowing the shortco- mings of the balance spring, he looked for another solution. He found one unexpectedly when he discovered that a combination of a pendulum attached to a balance is isochronous. He proved this mathematically and called the contrivance balancier marin parfait. The first such clock, BMP1, was entrusted to Barent van der Cloese to be built, but Huygens did most of the final adjustments. Landgraf Karl, who learned about it asked Huygens to make one for him but Huygens politely declined.8 It is plausible that Huygens changed his mind and the new clock, this one, was meant to be given to the Landgraf, which would explain the exceptionally elaborate case. In 1694 Huygens decided that his new invention will be based on two-arm balance (foliot)9 and a single small pendulum 10. These two features in 1695 he implemented into this clock, the BMP2.