Vacheron & Constantin Observatory Chronometer

May 05, 2010,18:03 PM

Vacheron & Constantin Observatory Chronometer:

A Hard Working Watch



Vacheron & Constantin, Genève, Chronometre No. 357355, case No. 229365.  Completed in 1914.  Very fine and rare 18K yellow gold keyless pocket chronometer with Guillaume balance.  Awarded Bulletin de Iere Classe and  IIIeme Prix au Concours de Genève from Geneva Observatory and Class A Chronometer certificate from Kew Observatory.


Case: four-body bassine 18K yellow gold, polished, back engraved with monogram: “M H L”.  Hinged gold cuvette with inscription of chronometer awards. 


Dial: white enamel with Roman numerals, outer minute track with Arabic numerals in five minute divisions, sunk subsidiary seconds dial. Pink gold spade hands. Original unsigned dial. 


Movement: 20’’’, gilt brass, 21 jewels, wolf’s teeth winding, counterpoised and calibrated straight-line lever escapement, anibal-brass Guillaume-type Integral Balance with gold and platinum poising screws, blued steel Breguet balance spring with double overcoil, swan-neck micrometer regulator.  Case and movement signed. Diam. 57 mm.


Geneva Timing Contest:

-Daily mean error                                             0.27 seconds

-Mean error by position                                   0.32 seconds

-Compensation error                                        0.010 seconds

-Rate resumption                                            -0.92 seconds

Archives of the Observatoire de Genève show the watch was tested from November 16th to December 30th, 1912, and granted a Bulletin De Marche on the 10th of January, 1913.  Adjusted by famed régleur C. Batifolier, the watch scored 733 points out of a possible 1000, placing 27th out of 109 tested and thus attained a 3eme Prix classification.


Kew Timing Contest:

- Mean variation of rate                                     0.49 seconds

- Mean change for 1 degree F                           0.076 seconds

- Extremes of daily rate                                     8.0 seconds

Records now kept at the Royal Observatory, Greenwich, show the watch was delivered by train to Kew Observatory on January 14th, 1913, in a batch of five Vacheron & Constantin watches.  The watch was tested from January 15th to February 28 and the results were entered in the Observatory records on March 5th, 1913. With 78.7 marks out of 100, this watch was awarded a Class A Chronometer certificate.


Observatoire de Genève

In 1766, the Royal Observatory of Greenwich organized the first timing competition on record.  In 1772, the Classe d’Industrie et de Commerce de la Société des Arts commissioned the Observatoire de Genève to administer chronometer trials for Geneva-based manufacturers.  The trials became so important for advertising purposes that other manufacturers later established facilities in the canton to qualify for competition.


Initially the Geneva Observatory required that a watch keep time to within 1 minute a day. Although 19 timepieces were submitted to the first trials, none were awarded the prize so the standard was subsequently revised to within 2 minutes per day.  When a new observatory opened in 1829, a timekeeper was dedicated exclusively to the Bulletin de Chronometre d’Observatoire trials.  Up until 1874, the manufacturers were free to submit their chronometers at any time, however, that year saw a complete revision of the rules.


An annual timing contest with a points system was introduced which proved to be a turning point for all Observatory competitions.  The new system awarded 1st, 2nd, 3rd and honourable mention prizes for the best timekeeping within the categories of marine chronometer, deck or pocket chronometer, and chronometer with complications.


Watches which successfully passed the tests were issued a Bulletin de Marche, certifying the results obtained.  Watches which scored more than 2/3 of the available points were published by the Société des Arts until 1927, then by the Publications de l'Observatoire de Genève until 1968. Over the years the method of scoring underwent some changes, most significantly when the total points available increased from 300 to 1000.





The results are presented in this form:

Daily mean deviation=m

Mean deviation by position=d

Error compensation=c

Rate resumption=r


Method of calculation points:

2 categories; A and B, but only one formula for both categories.

The category is defined by the diameter of the chronometer.

Class A diameter is less than 43 millimeters.

Category B is larger than 43 millimeters.

A new formula is applied in order to better distinguish the competitors.

The old formula is still present in the results.

The values m, d, c and r are expressed in hundredths of a second.


Old formula:

Total=300 points (0.75-m) * 400 / 3 + (2.5-p) * 40 + (0.20-c) * 350 + (5.0-r) * 6

Absolute perfection 300 points


New formula:

Total=1000 points (0.50-m) * 600 + (2.0-p) * 150 + (0.150-c) * 2000 + (2.5-r) * 40

Absolute perfection 1000 points


Ideally, competition timepieces were attended by one of an elite group of precision adjusters, or régleurs, who were known to every watch professional in the country.  The most famous were C. Batifolier, M. Favre, J. Golay-Audemars, F. Modoux, E. Olivier, H. Wehrli and A. Zibach.  Mr. Batifolier was especially renowned at Vacheron & Constantin after he obtained a 1st prize for the manufacturer at the Geneva Observatory Trial of 1898.


The following translation is an excerpt from the annual report of the Classe d’Industrie et de Commerce de la Société des Arts on the 1917 Geneva Observatory chronometer trials, Mr. Batifolier was in the employ of Patek, Philippe et Cie on this occasion, however, François Modoux represented Vacheron & Constantin most adequately.







Meeting of Wednesday, February 20, 1918, under the chairmanship of Mr. A. Bétant President


Mr. President delivered a eulogy of Mr. Moses Lighter, a member of the Class, and informed members that the deceased gave us a legacy of Fr. 200. The congregation stands to honor the memory of our colleague.


Report R. Gauthier on the support of chronometers in 1917.  The floor was given to Mr. Director of the Observatory for his report on the contribution of chronometers in 1917. Gauthier announced that 132 first timers, including a Marine, have been deposited at the Observatory, against 106 in 1916; 128 in first class and in second class only three. Of these 128, 112 have received the Bulletin and 16 have suffered a failure. An interesting fact is that none of the failures are due to compensation events or changes in temperature, although they are very difficult.


90 pieces took part in the contest, 19 were filed twice and three were of foreign origin.  These 90 pieces were submitted by seven manufacturers and regulated by twelve adjusters.  The result of the contest:


Contest of isolated parts


First prize 

Points              Manufacturers                                     Regulator        

842                  Vacheron and Constantin                    Modoux

831                  Patek Philippe & Co.                           Batifolier

809                  Vacheron and Constantin                    Modoux

808                  Vacheron and Constantin                    Modoux

807                  Patek Philippe & Co.                           Wehrli

805                  Vacheron and Constantin                    Modoux

801                  Patek Philippe & Co.                           Golay-Audemars


Second prize

799                  Vacheron and Constantin                    Modoux

795                  Vacheron and Constantin                    Modoux

785                  Patek Philippe & Co.                           Golay-Audemars

777                  Patek Philippe & Co.                           Batifolier


Competition of series


First prize


I. Manufacturers

812.8               Vacheron and Constantin

800.8               Patek Philippe & Co.


II. Adjusters


First Prize

812.8               Modoux


Second prize

780.0               Golay-Audemars


Third prize

745.6               Batifolier


Honorable Mention

716.4               Wehrli


Special Awards


Prize, average difference daily

Vacheron & Constantin

Regulator:       Modoux


Prize, average timing

Patek Philippe & Co.

Regulator:       Addor


Prize, Premier Bulletin.

Regulator:       Rishon


Mr. Bétant thanked Prof. Gauthier for his very interesting report and then gave the floor to Mr. J. Mauler for his talk on the mechanism of Jaquet-Droz automata.  Mr. Mauler who worked himself to the setting of these machines when they returned to Neuchâtel, possesses a perfect knowledge, which ensured a special interest in his presentation.


A similar competition system was followed in 1884 at the Astronomical Observatory of Kew, England, then in 1885 by the Besançon Astronomical Observatory in France.  Unfortunately, the tests were never standardized between countries so a comparison of results was not encouraged.


Kew Observatory

Kew Observatory was built by George III in 1769 to observe the Great Transit of Venus.  From 1842 to 1871 it was run by the British Association for the Advancement of Science and from 1871 through 1899, by the Royal Society.  The observatory was taken over by the National Physical Laboratory in 1900.  Sextant certification work was transferred to their Teddington facility in 1910 and chronometer testing followed in 1912.  The Teddington laboratory continued to use the well-known K.O. mark for Kew Observatory.


On July 15, 1914, Kew achieved the distinction of granting the first chronometer certificate to a wristwatch; the ubiquitous Rolex.  By 1974, all Observatory trials were discontinued after the mass-marketing of quartz movements made accuracy a certainty.


Then And Now

For two centuries, Observatory Trials were the ultimate test of chronometry.  Movements of superior technical design, perfect finish and expert regulation were selected from inventory or manufactured for the purpose.  The pinions and wheels were polished to exceptional tolerances, hairsprings were pre-tested and hand-picked, and the dimensions of shafts and bearings were perfectly machined. 


The movements were then fixed to square blocks, for easy handling, and enclosed in aluminum or wooden cases for transportation.  Unsigned dials and plain hands were often used as aesthetics were not a consideration.  After 45 days of continuous testing in 5 positions and 3 temperatures (4°C, 20°C and 30°C), the most precise chronometers were awarded honours for the year while manufacturers enjoyed the publicity and resulting sales.


Observatory Chronometer movements were kept by their manufacturers for years, even decades, and few were released for sale as complete watches.  One can only imagine what the esteemed régleurs of the past would think of modern times, with over one million Chronometer certificates issued annually.


They would probably feel distressed knowing that today a far less onerous test is necessary to achieve the designation of Chronometer.  Administered over 16 days by the Contrôle Officiel Suisse des Chronomètres (COSC), movements are now required to meet these Exigences minimals:


·        Mean daily rate in 5 positions (Mav)                                               -4/+6 seconds

·        Mean daily rate variation in 5 positions (Vav)                                   2 seconds

·        Maximum variation in 1 position (Vmax)                                          5 seconds

·        Difference between vertical and horizontal rate (D)                          -6/+8 seconds

·        Greatest difference between mean and daily rate (P)                        10 seconds

·        Thermal variation per °C (C)                                                           ± 0.6 seconds/degree

·        Difference between first and last daily rate (R)                                 ± 5 seconds


The current regime of chronometry testing has evolved away from the principles underlying Observatory Trials.  Today’s chronometer is “good enough” if it meets minimum standards (95% of movements tested are passed) whereas the trials of the past rewarded only the top few.


Observatory Trials Reborn

Exciting news was received in 2009 when the Concours International de Chronométrie timing competition was undertaken to celebrate the 50th anniversary of the Museum of Horology in Le Locle.  The issuance of timing certificates by the Glashütte and Besançon Observatories and rumours of a similar British enterprise under consideration must certainly have provided additional motivation to reawaken the heritage of time trials.


The Chronométrie 2009 Concours was conducted in three stages involving four locations.  The watches started at the Besançon Observatory in France, where they were subject to the standard 16 day COSC test.  They were next shuttled to COSC in Biel, where the 16 day trials were repeated.  Then followed a side trip to Le Locle where the watches were subjected to shock and magnetism stresses before being sent back to Biel for a third round of tests following the standard COSC formula:


N=1000 – [(500 x │C│) – (100/3 x │D│) – (100 x Vav) – (10 x P) – (20 x Vmax) – (10 x │R│) – (12.5 x │Mav│)]


The final score was obtained by adding the tests: N Final=(0.4 x N1) + (0.4 x N2) + (0.2 x N3).  As can be seen, the tests following shock and magnetism were allotted less weight.  Organizers were undoubtedly relieved when the small risk they undertook to introduce those two new standards did not induce any degradation of scores. Furthermore, while not stated in the publicity literature, one might wonder if adjustments were permitted between stages considering the transportation involved.  Research in this area was hampered by the discovery that, soon after the winners were announced, the competition website went offline.


This first Concours was a tentative affair, only open to European brands.  The “International” label apparently referred to the inclusion of France as a testing venue.  The format did not correspond with traditional Observatory competition and was rife with compromises.  Results were kept anonymous but for the category winners.  Of sixteen wrist watches that began, six were eliminated during the trials, including five at the first stop in Besançon.  Just as well that Vacheron Constantin was absent from the fray.


Based on a perfect score of 1000, Jaeger-LeCoultre gathered 909 points with their Master Tourbillon Cal. 978 to win the Brands category, while René Addor received 795 points with his Calibre Papillon for seventh overall and top score in the Independents category.  Despite official secrecy, the guerilla press disclosed the failure of Audemars Piguet’s entrant was due to a broken spring, while watches from Voutilainen, Chopard, Randin and Journe were also tagged as non-finishers.  Many expressed surprise with the severity of the tests and admitted to their lack of preparation.  The most admirable performance must be accorded to René Addor who achieved victory with a prototype that he completed in his basement studio just prior to the event.  Perhaps he has some kinship with a régleur of the same name who appeared in the 1918 report of the Société des Arts.


Watch enthusiasts should be overjoyed at the resumption of chronometer competitions, but there is much to consider before the next Concours in 2011.  A resurgence of interest in mechanical accuracy, contrasted with the acknowledged irrelevance of standard COSC measures, has created a demand for truly competitive trials.  Should the organizers and participants embrace the concept with greater commitment and transparency, modern horology will surely benefit.  With some encouragement, Vacheron Constantin may even seek to reclaim past glories!


Best Regards,

Dean aka TickTalk

May 5, 2010




1.      Minutes of the Annual Meeting of the Classe d’Industrie et de Commerce de la Société des Arts, February 20, 1918

2.      Chronometre Royal 1907: 100 Years of Flamboyance by Alex Ghotbi

3.      History of Omega Observatory Trials and Precision Records by Michael Ting

4.      Antiquorum Biography: François Modoux

5.      Secrets of Vacheron Constantin by Franco Cologni

6.      Time on Trial by Justin Koullapis, QP magazine

7.      Revelations of a Secret Competition by Alan Downing, Watch Around magazine

8.      Observatoire de Genéve website

9.      Contrôle Officiel Suisse des Chronomètres website

10.  La Commune du Locle et le Musée d’Horlogerie du Locle press release




·        I would like to thank Rory McEvoy, Curator of Horology at the Royal Observatory National Maritime Museum, Greenwich, who responded most enthusiastically to my research requests.

·        The Observatoire de Genéve requires a fee of CHF 200 to re-issue a Bulletin de Marche.

·        International Organization for Standards (ISO) will provide a copy of the current Standard 3159-2009 Timekeeping Instruments: Wrist Chronometers, for CHF 50.

·        Further reading on COSC and its relationship with the watch industry may be found at in an article by Alan Downing titled ‘Inside COSC’.

·        Charles-Édouard Guillaume was 51 years old when this watch competed in time trials with his revolutionary Anibal composite balance wheel, which he referred to as a Balancier Intégral.  In 1920, Guillaume received a Nobel Prize for the invention of Invar and Elinvar, and thereafter the term “Guillaume balance” was commonly applied to the Integral Balance in recognition of this fame.  In his Nobel lecture, Guillaume suggested one “slight defect” with the widespread use of his alloys in chronometers; the régleur may no longer be required.


* All photos are property of the author and may not be reproduced without consent smile


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Comments: view entire thread


Impressive research, Dean...

 By: WHL : May 5th, 2010-19:45
Thank you for writing and posting this well researched article. I especially appreciate the history of the Chronometer competitions from days past and the contrast with today's standards. I hope that the renewed competitions are embraced by the brands. I ... 

Yes it is, Bill (nt)

 By: Tick Talk : May 6th, 2010-08:20


 By: dshao1 : May 5th, 2010-20:07
Hi Dean, This stuff is unbelievable and what I've been looking for! Thank you ever so much for this extremely informative post! I've only read it once. But will have to print it out and go over it very carefully to extract as much of that information and ... 

VC and Chronometer Ratings

 By: Tick Talk : May 6th, 2010-08:33
Thanks Dan Your comments are greatly appreciated, knowing how much of a Chronometre Royal fan you are. I'm looking forward to hearing about your research on the CR pocket watch chronometer ratings. An interesting fact that I haven't yet explored was the p... 

I've sent a message to the Geneva Observatory

 By: dshao1 : May 6th, 2010-19:25
Hi Dean, As you mentioned in the end notes of your research, re-issues of Bulletin de Marche are available if requested. Therefore I sent them an inquiry about two Chronometre Royal watches. Considering the "high production volume", I can understand that ... 

Dan, I am surprised

 By: PoyFR : May 10th, 2010-22:13
On occasions I write to watch companies, some do not bother to reply. But at Vacheron, I always received a reply/replies Sometimes it is a good idea to initiate a communication with a phone call, then you get the person contact details you really ought to... 

I think it may have gotten lost in translation?

 By: dshao1 : May 11th, 2010-01:08
Hi PoyFR, My communications with VC over the past couple of years have ranged from exceeding outstanding to poor. I made these types of inquiries to VC when I sent my watches back to Geneva for full restoration and Certificates of Authenticity. I discover... 

An update

 By: dshao1 : May 11th, 2010-21:30
I've been talking to the VC Concierge in New York about what type of documentation came with 2 vintage Chronometre Royal watches (1908 pocket watch and 1955 wristwatch) that I have and if it was possible to obtain copies of any type of testing results, wh... 

My vintage Chronometer Royal wristwatch from the 1950's

 By: WHL : May 12th, 2010-07:19
came with a COSC certificate, but nothing from the Observatory. This is not as rigorous as the Oberservatory tests, but still a nice to have, and unusual for a watch from that time period. Unfortnately I lost all my paperwork that came with the watch, and... 


 By: Tick Talk : May 12th, 2010-07:21
I feel for you Bill. Perhaps time will dull the loss...

I like having everything accompanying the watch...

 By: WHL : May 12th, 2010-07:43
but not having the accessories doesn't take anything away from the intrinsic greatness of the watch. That vintage Chronometer Royal is still one of my keepers! Bill

are you sure the COSC certificate was not given at a later date as

 By: alex : May 12th, 2010-07:52
COSC was created in 1973 wheras your watch is from the 50s!


 By: WHL : May 12th, 2010-07:56
Now I've got to go find the photo I took of the certificate (which might only be on a computer I no longer have), since I don't have the certificate itself....Do you have access to the papers that accompanied the the early Chronometer Royal wristwatches? ... 

Hi Bill, I recall seeing the timing results of your 1950s CR

 By: dshao1 : May 12th, 2010-16:45
in a post sometime in the past. I do not believe it came from COSC, it came from VC though I'm no longer sure who did the testing. This is also one of the reasons I was surprised that my 1950s CR does not appear to have been tested, or if it was tested in... 

Timed When Serviced

 By: Tick Talk : May 13th, 2010-07:02
I'd speculate that when Bill's watch was serviced or restored, it was also adjusted and a record was provided of the results.

Picture of a similar document?

 By: dshao1 : May 13th, 2010-15:39
Hi Bill, I found this picture of a VC Chronometre Royal "Bulletin de Marche", did your document look something like this? It is blank, which confuses me a little, so I'm not sure if it's authentic. If it is authentic, I don't understand why all CRs wouldn...  

In-house Chronometer Certificates

 By: Tick Talk : May 13th, 2010-17:39
Here is a completed certificate from V&C (image courtesy of Purists). Sorry for the bad focus but I had to enlarge it. I believe these documents were for watches tested in-house. Interesting to note that "especially good" was pre-printed on the blank form...  

I sent an inquiry to the VC concierge

 By: dshao1 : May 13th, 2010-23:28
and we should know, definitively, what these certificates represented pretty soon. BR, Dan

Early COSC certificate

 By: Tick Talk : May 22nd, 2010-07:50
This early COSC certificate for a Rolex shows "Especially Good Results" also pre-printed on the form. The original Observatory Trials only assigned that distinction to movements that scored 80% of available points versus the passing grade of 66%....  

Great post - loved reading it. The research behind it is evident and

 By: 219 : May 6th, 2010-05:55
I am so happy that someone has posted such an informed article on the Timing competitions and why they should return. I can only endorse your views by at least (and certainly no less) than 100 percent (or 1000 points). Great posting and thanks for doing s... 

It's about TIME too...

 By: Tick Talk : May 6th, 2010-08:46
Sorry for the pun, Andrew ;-) It has been frustrating for us gear-heads that, for the past several decades, issues of aesthetics and design overwhelmed the basic fundamentals of good timekeeping. I think a certain defeatism occurred following the quartz c... 

Completely agree. I found it fascinating that the same

 By: 219 : May 7th, 2010-03:05
basic escapement that was winning Observatory trials in the 1940's (JLC Calibre 170) was again winning some 60 years later. Have a look at the escapement and bridge design - extraordinary. Vacheron were one of the clients of the 170 base ebauche who then ... 

I would also chime in with...

 By: watchme : May 10th, 2010-05:38
the fact that many of the "high end" clients between 1870 and 1940 purchased their ebauches from JLC, and to see JLC take first and second place - with the points awarded, considering the above article - makes me stick my chest out proudly for the greatne... 

Very informative article

 By: SJX : May 10th, 2010-04:52
Thanks Dean. I think the chronometry contest next year will be better attended and will also have a higher rate of success, as manufacturers now know what it entails and how the watches should be prepared. - SJX

Lets hope so! (nt)

 By: Tick Talk : May 10th, 2010-07:20

Many thanks for your post. Only a 'few' do the real work

 By: PoyFR : May 10th, 2010-22:07
The information within your post is well prepared, informative and rich. We do not often realize the importance of true and long lasting works as it is often hidden behind materials and hypes. I welcome all those new tests about mechanical watches, they w... 


 By: patrick_y : May 11th, 2010-00:42
Very impressive watch. Vacheron Constantin's claim to fame (as well as Patek Philippe's claim to fame) and success in many parts of the world was directly related to the results of these Swiss Chronometer tests. It's really impressive to see all this info... 

Reissued Observatory Bulletin

 By: Tick Talk : May 20th, 2010-07:45
The Observatory Bulletin arrived yesterday, as reissued by the Geneva Observatory which is now part of the University of Geneva. After they confirmed by email that records of my particular movement existed, for a fee of CHF 200 they sent PDF copies of the...  

Very nice, a great document to go with a VERY special watch!

 By: dshao1 : May 21st, 2010-00:46
Hi Dean, I think having that type of documentation really complements the watch. Congratulations. Have you timed the watch itself to see how it is running now? Any thoughts of having VC restore (if necessary) and trying to regulate it to the best of their... 

Pocket Watch Revival

 By: Tick Talk : May 21st, 2010-16:23
It is pretty impressive that you wear your pocket watch Dan Mine is just hanging in the display cabinet so I'm not too concerned about timing. At 57mm it's a mite big for daily use but I am very tempted to start wearing the X-thin once I buy a few shirts ...  

I've been interested in pocket watches since I was a teenager

 By: dshao1 : May 22nd, 2010-00:02
Hi Dean, The first PW I ever bought was through a catalog store, Service Merchandise, in the late 70s/early 80s. I've always been a little non-conformist The CR, being an antique, is not a watch I plan on using long-term in a daily manner. I just wanted t...