Observatory Chronometer: A Hard Working Watch!

Observatory Chronometer: A Hard Working Watch!
Author's Photo

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. 

Observatory Chronometer: A Hard Working Watch!
Author's Photo

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. 

Observatory Chronometer: A Hard Working Watch!
Author's Photo 

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. 

Observatory Chronometer: A Hard Working Watch!
Author's Photo

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. 

Observatory Chronometer: A Hard Working Watch!
Author's Photo

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. 

Observatory Chronometer: A Hard Working Watch!
Author's Photo

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 

Observatory Chronometer: A Hard Working Watch!
Author's Photo

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. 

Observatory Chronometer: A Hard Working Watch!
Example Kew Observatory Certificate from 1904, anonymous from the Internet

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. 

Observatory Chronometer: A Hard Working Watch!
Master Adjuster Edmund Olivier circa 1950, image courtesy of Cologni's Secrets of Vacheron Constantin

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. 

Observatory Chronometer: A Hard Working Watch!
Image courtesy of La Commune du Locle et le Musée d’Horlogerie du Locle

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

Notes • 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 TimeZone.com 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.
Dean, I congratulate you to this magnificent piece!
05/06/2010 - 21:15
Stunning is a to often used word in our posts, but in this case it's true. First of all a beautiful watch adding to that all the documents, makes it to a real treasure Funny they used the same movement in 1920, It's inside this my favourite pocket watch! And I can tell you that it's working just perfectly, + 2-3 seconds per 24 hours! Thanks again for sharing your beauty with us Cheers Doc
The Heart of the Matter
05/07/2010 - 02:55
BTW, check out lot 186 of Sotheby's May watch auction...it's a 1932 Observatory Tourbillon pocket watch that competed in 1931 and again in 1944.  Both times it was regulated by Edmund Olivier and on the first try won 1ere Prize.  It was finally cased and sold in 1946.
This is 1919's heart!
05/07/2010 - 18:10
An amazing and thorough piece. I can only laud the rebirth of these
05/07/2010 - 11:24
trials but I find that last year's Swiss trials were suurrounded by way too much secrecy, we did not know of the participants, the tests, the way the watches were graded etc... But its encouraging for the next years as a good alternative to the COSC whose standars I find not stringent enough considering that the materials used today can enable better adjustment and regulation. This is going into the Recommended Threads section
Time for COSC to catch up!
05/08/2010 - 00:07

When the Observatories got into chronometer testing, they offered the basic 45 day trials plus the competitions for those movements that scored above the 2/3 threshold.  I would hope that COSC and partners decide to re-establish this format.  Then they can pass those 1 million plus "regular" chronometers out the door as usual, plus add an exciting new element of competitive trials for those who wish to go above the threshold. For manufacturers, the risk is that cheaper movements may win over those high-end brands who advertise all kinds of technical marvels that do not improve accuracy and/or decrease reliability.  Guess what...Tissot and Swatch tied for fourth place in the 2009 Concours, behind a trio of super-expensive tourbillons, with standard ETA movements!!Good, I say, let's out the poseurs

Wow! Thank you for this very informative article, Dean.
05/07/2010 - 14:49

I agree with you and Alex on the merits of reviving the trials and wish that, when a more appropriate set-up becomes available for the trials, VC will join in and hopefully regain its historical position at the top. Thank you again for this great article.  I can only imagine the tremendous work that you put into its preparation! All the best, Kazumi

Tremendous Inspiration
05/07/2010 - 23:57
Hi Kazumi!  Having the watch in my hands was tremendous inspiration for researching and writing the article.  Now I'd like to know who the original owner was that inscribed their initials on the back!  All of the engraving is still sharp to the fingertips so I'd guess this piece didn't see much "pocket time"  although the inner cuvette has four seperate service markings.
a work of horological investigation, thank you
05/07/2010 - 15:48
Your welcome :-) (nt)
05/08/2010 - 00:08
Great post Dean!
05/12/2010 - 08:38
Hi Dean, As I've already mentioned to you both on and offline, I love this post and have learned a lot from it! Following-up to what you provided, I had renewed interest in seeing what type of testing information was available for my 2 Chronmetre Royals. I've been talking to the VC Concierge in New York over the past week about what type of documentation came with my 2 vintage Chronometre Royal watches (1908 pocket watch and 1955 wristwatch) and if it was possible to obtain copies of any type of testing results, whether it was from an Observatory or the Maison.  I received the following reply this morning: Dear Mr. Shao,

I was able to speak with my colleagues in Switzerland regarding your request.

Unfortunately, Vacheron Constantin does not keep a register of the Observatory Testing results for our timepieces.  Therefore, it is not possible to obtain copies of the original documents that may have come with those timepieces through Vacheron Constantin.  You would have to speak directly with the Observatory of Geneva for those documents.

However, the Heritage Department also told me that there is no mention in the archives of your two particular pieces having original documentation from the Observatory of Geneva.  The "Chronometre Royal" is a trademark and does not guarantee that all the movements received a certificate from the Observatory.  The two particular pieces you own may have never had this documentation.

I was surprised as I must have misinterpreted what "Chronometre Royal" stood for.  I knew that it was a trademark copyrighted in 1907, but believed the watches that bore the name were considered "Chronometres" of their time, and therefore needed to pass this type of testing in order to be considered Chronometres.  Or at least some type of  "series" or sample testing (since over 10,000 CR pocket watches were manufactured over a period of 30+ years, I recognize the impracticality of trying to test every one at an Observatory - let alone having every one pass!). I still think the 2 watches I have are beautiful, but I'm just a little disillusioned. Best Regards, Dan
I believe the term "chronometer" as in precise measuring instrument
05/12/2010 - 12:18
was officialised by the creation of COSC and normally only COSC tried pieces can be called Chronometer which I find misleading as the generically all timepieces are chronometers!
A Chronometer By Any Other Name
05/13/2010 - 00:35
I guess we should review the use of the term “chronometer” over the years. The origin circa early 1700’s was developed from the Greek and means to measure time. It was first applied to ships chronometers, which were rare and delicate while being the most accurate watch available. The term was applied more generically to early pocket and wristwatches until COSC trademarked its use exclusively for watches that pass their testing. So today, although many other watches would equal or better COSC standards, they could not be called a chronometer…go figure! Before wristwatches, Vacheron Constantin only inscribed Chronometre on the cuvette of pocket watches that had passed Chronometer testing at one of the Observatories - most commonly Geneva.  Observatories had two levels of testing; the basic 45 day trials which, if passed, awarded a First Class certificate (Premiere Classe Bulletin).  Those VC pocket watches without any other inscription besides Chronometre passed this level.  Those that scored higher were entered into the Competition (Concours) trials against other top watches and would compete for 1st, 2nd, 3rd prize or honorable mention.  VC would often engrave these awards on the cuvette if and when the movement was cased.  These competitions were only held once a year at each Observatory so a great deal of attention and preparation was provided for them. As with everything else, once the Observatory trials were well-known the term Chronometer, Chronometre and Chronometro became irresistible for marketing and started to show up on watches that had not been tested. This is the case for the Chronometre Royal line of pocket and wristwatches, Waltham's Chronometro Supremo and Chronometro Victoria, Patek’s Chronometro Gondolo, etc.   What finally led to the creation of COSC and protection of the term for their exclusive use in wristwatches is a matter of some controversy.  For one perspective, let me again quote Alan Downing from one of his outstanding Watch Bore articles at TZ:The objective assessment and testing of civilian watches started in the railway age when confidence in the timekeeping qualities of your watch became paramount. Observatories and laboratories in major cities rated timepieces. Manufacturers competed for prizes. Customers paid premiums for high-rated watches. COSC differs in one important respect from all previous watch testing institutions and observatories. It is strictly non-competitive. There are no points awarded or any prizes. There are no degrees of success or honorable mentions. The watches either pass or fail. This was the one condition demanded by the Swiss watch industry when COSC was founded in 1973. Until that time, there were two institutions in Switzerland that issued rating certificates to watches. The observatories rated prepared timepieces, held competitions and awarded prizes. Local testing laboratories in seven watch making towns issued rating certificates to time-of-day watches. These were grouped into an association called ABDO. ABDO rating certificates gave commendations such as "especially good" to deserving movements. Ninety percent of the watches submitted to ABDO laboratories were from three brands — Rolex, Omega and Mido. In 1972, an important delegation of Swiss watch manufacturers went to see Mr René Meylan, then industry minister in the Neuchâtel cantonal government. They demanded the end of the observatory competitions. The reason: the Japanese had swept the board in the last two events. Mr Meylan replied that he thought that the whole point of the competitions was for the best to win. The brands then threatened to boycott the contests. Meylan gave in. The observatory competitions were suspended and never revived. At the same time Rolex, Omega and Mido started to dismember ABDO. By selectively boycotting one or other of the seven testing laboratories they caused each to grant increasing discounts and favors until the organization collapsed. Mr Soguel says COSC does not compile or publish comparative results because there is no demand for it from the brands. He compares the COSC certificate to a university degree. "It certifies that you have reached a certain standard, but it does not guarantee that you can still pass the test 20 years hence. And when you frame your diploma on your office wall, you don’t mention the marks you got." Were COSC to introduce any sort of ranking by test results, Swiss watchmakers would be forced to compete on the intrinsic qualities of their watches and the whole value hierarchy of Swiss watches would be overturned. That COSC and others in the industry were prepared to ever-so-gently dip their toe back into the heated waters of true competitions with the 2009 Chronometre Concours is very good news.  Flawed as they were, we can hope that it leads to a renewed focus on mechanical timekeeping and perhaps signals the end of the gargoyle school of watch design over function.
Very interesting follow-up Dean
05/13/2010 - 04:30
Thanks Dean, I'm now a bit embarrassed by falling for a 100+ year old marketing scheme Shame on you VC , its a very good thing that I still these two: BR, Dan
Nothing but pride...
05/13/2010 - 17:56
You should feel nothing but pride, Dan .  The term "chronometre" wasn't owned at the time and Patek had launched the nomenclature Chronometro Gondolo based on their special-order pieces in South America.  The fact that Waltham then Vacheron also tagged it onto similar ventures is just an interesting example of how markets and branding develop. Your beautiful examples illustrate the outstanding quality and design that were invested in the Chronometre Royal line...much more than just a name!
More Photos
08/16/2011 - 19:32
Oops, I accidentally deleted the pictures hosted on flickr, so here they are uploaded to this site.