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A Marine “Survey” Chronometer, Geodesy, and the Measuring of a Meridian Arc in Argentina

- By Burt Cifrulak (PA) 10/30/20

A marine chronometer in its wooden case and gimble
Figure 1. The subject of this story, the Ulysse Nardin marine chronometer, built in 1939, equipped with a break circuit device for survey work. Note the correct period-style factory winding key.

“To me, a ship’s chronometer is an exquisite timepiece, and because it demands the highest degree of skill and craftsmanship, it is undoubtedly the pride of the horological world.”

—Marvin E. Whitney, The Ship’s Chronometer


Surveying, or “land navigation,” was an important function of governments and other authorities who wanted to define and substantiate their geographical boundaries and mark other important land features. To successfully carry out the surveying and mapping operations of land masses and coastal shores, it is necessary to have precise, portable time. To meet this need, the break circuit or survey chronometer was developed (Figure 1).1

Recently, I had the opportunity to acquire a very fine Swiss-made marine chronometer by Ulysse Nardin, a long-tenured and well-known brand. I thought the instrument’s history had the potential to make a good story, and it was made by a firm that I have not featured before in any of my articles. What I learned was this chronometer was ordered and purposely built for yet another demonstrated use that these remarkable and accurate portable timekeepers accomplished.

Ulysse Nardin

Today, Ulysse Nardin is a well-known and respected maker of luxury Swiss watches with a history spanning more than 170 years. The company has become one of the world’s foremost chronometer manufacturers.2 Over the years, the brand has been awarded 18 gold medals as well over 4,300 awards and observatory prizes (London, Paris, Chicago, Milan, Buenos Aires, Berne, Genoa, Liege, Tokyo, Genoa, Barcelona, Zurich, New York, Liege, and Lausanne) for excellence in horology, and today is a leader in watch innovation. Like most successful watch businesses, the firm started with humble beginnings.

Born in Le Locle, Switzerland, in 1823, Ulysse Nardin would become the founder of the famous firm that would bear his name.3 He began his apprenticeship under his father, Leonard, who was the first watchmaker in the family. He received additional training with the finest watchmaker in Neuchatel, William Dubois. A skilled craftsman, Ulysse established the firm in 1846, making repeater and very complicated watches and pocket chronometers.4 These finely made watches increased his recognition and status at international competition events, winning prizes in London in 1862, and in Vienna in 1873.5

The distinguished horologist Henry Rosat joined the firm in 1866 and spent 31 years of faithful service to the brand, contributing in many ways to its success. With his valuable assistance the firm entered into the newly established Swiss government’s set of standards and testing of chronometers at the Neuchatel Observatory in 1868, winning the first two awarded prizes for chronometers.6

In 1876, Ulysse died suddenly at age 53. Leadership of the firm passed to his son, Paul David, when he was only 20 years old.7

Paul David Nardin

Paul David (1855–1920) was reported to be a fine adjuster of chronometers even at the young age of 17 years old.8 He was working as a chronometer finisher at the company, and he won his first gold medal at the International Timing and Adjusting Competition in Geneva only two months after his father’s death. It was after this competition when he, now at the company’s helm, decided that the firm would concentrate on the manufacturing of marine chronometers.9

In 1899, Nardin was the first chronometer maker to approach Dr. Charles Guillaume, Director of the International Bureau of Weights and Measures at Sevres (near Paris), after his discovery of the new alloy Invar in 1897.10 Nardin, in adopting its use in the balance of chronometers, was able to reduce or eliminate middle temperature error. The firm was the first to place a chronometer on trial with one of the new balances with very positive results. In one test the middle temperature error of the same chronometer, after modifying with the new balance, was reduced from 1.9 seconds to only 0.3 second, which Whitney described as “a remarkable achievement.”11 Nardin had great success with selling its marine chronometers to the U.S. Naval Observatory (USNO) in 1902 for use in Navy service. The Nardin marine chronometer 3806 was loaned to Hamilton during 1940 by the USNO, serving as a model to study for design purposes. Fitted only with the new Hamilton balance and hairspring, the chronometer was returned for testing to the USNO, earning outstanding results.12 The basic design of the Hamilton chronometer was very similar to that of the Nardin. If the saying “imitation is the best form of flattery,” then also add Seiko of Japan during World War II to the list, as it copied the Nardin marine chronometer exactly, even down to the red wax used in the numerals of the dial.13

Paul Nardin had three sons, Alfred, Ernest, and Gaston, and they would all enter the firm to carry on the family business. Auguste, the son of Henry Roast Jr., would also serve in the business, making three generations of the two families, guiding and winning awards at Observatories of Geneva and Neuchatel. Whitney noted that “although there were several very fine and notable Swiss chronometer makers who made many valuable contributions to the science of chronometry, those close to the scene say unquestionably that Nardin was solely responsible for the progress and promotion of the Swiss marine chronometer industry.”14 In the early part of the 20th century the company could boast that more than 50 navies and international shipping companies used Ulysse Nardin chronometers for navigation purposes on the seven seas. Mercer estimates Nardin marine chronometer production at 4,000 units.15 The company was sold in 1983 during the “Quartz Crisis” to Rolf Schnyder, who would eventually bring it back to its former glory, producing modern versions of high-grade and luxury wristwatches.


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Break Circuit Chronometers

To meet the demand for precise, portable time in surveying and mapping operations, it was necessary to have accurate and audible time signals. The break circuit, or survey chronometer (the equivalent English term), was developed, designed, and produced. A standard 56-hour ship’s chronometer was used, to which a break circuit device and electrical contact system was installed in the movement.16 The Negus brothers , Thomas S. and John D. are credited as the first to install the device on a chronometer in America in 1874.

With this modification in place, an electrical circuit is opened and closed by the mechanical operation of the chronometer at a specified interval (variable by design), which when connected to a set of headphones or sounder gives a remote observer an audible and accurate time signal or tick. The instrument so fitted can also be connected to a chronograph and recording drum if required.

In 1877, the Spanish Geographical Institute authorized collaboration with Nardin in designing the company’s first break circuit chronometer.17 This break circuit mechanism was very similar to the ones being used on instruments of other makers. The company produced 50 of these instruments for numerous scientific institutions throughout the word during the period between 1883 and 1910. With these successful sales, Nardin as early as 1910 was petitioning the USNO to purchase its model of break circuit chronometer.18 This innovation and modification was also used in other areas of science, such as astronomy, with great success.

A Nardin marine chronometer movement
Figure 2. Nardin marine chronometer movements are well designed and sturdily built. Visible in this picture are the break circuit contacts. It was this type of 56-hour model movement that was loaned by the U.S. Naval Observatory to Hamilton designers and engineers to study for reference in building their own instrument, the Model 21.
A Nardin marine chronometer movement
Figure 3. The chronometer is fitted with a spring detent escapement and bimetallic compensation balance with an antimagnetic helical hairspring.

Nardin Marine Chronometer 3401

The Nardin marine chronometer 3401 is a well-designed and well-built 11-jewel, 56-hour (2-day) KWKS, fusee and spring-driven instrument (Figure 2). It is fitted with spring detent escapement and bimetallic compensation balance with antimagnetic helical hairspring (Figure 3). The movement is four-pillar in design and has gilt plates. The chronometer is equipped with a break circuit that breaks a circuit every second except the 60th second. This non-break allows for a warning to the operator that the new minute is about to start. The break circuit is complete with all electrical connections even featuring the original spark-arresting condenser that is seldom seen (Figure 4a). As the device was complete as found, a simple sounder was constructed to test its function. The test proved the chronometer break circuit was working as designed so many years ago (Figure 4b). The Nardin and Hamilton chronometers both share an uncommon feature: an adjustable detent.19 No doubt it was something the designers and engineers at Hamilton decided was a feature they wanted to keep from Nardin in their initial design. The dial is silvered with Roman numerals and signed “Ulysse Nardin, Suisse, 3401” (Figure 5). According to Nardin, the built date on this instrument is 1939. Mercer’s estimate put its built date at 1941.20 All three original hands—hour, minute, and power reserve—are blued steel. The Spanish words “COMISIÓN PARA LA MEDICIÓN DE UN ARCO MERIDIANO LEY 12334” were marked on the bezel by the factory (Figure 6). The English translation is “COMMISION FOR THE MEASUREMENT OF A MERIDIAN ARC LAW 12334”. This indicated to me that the chronometer was specifically ordered from Nardin for a special purpose by a government or government agency.

The chronometer and its gimbal suspension setup are housed in a well-built and very attractive 3-tier, brass-bound ribbon-cut Honduran mahogany box, measuring 7 ½” x 7 ½” x 7 ¼”, with signature plate and gilt drop handles (Figure 7).

The factory break circuit device is complete with all electrical connections intact, including the rarely seen spark-arresting condenser
Figure 4A. The factory break circuit device is complete with all electrical connections intact, including the rarely seen spark-arresting condenser.
A simple sounder device was constructed to test the function of the break circuit, which proved to be working as designed
4B. A simple sounder device was constructed to test the function of the break circuit, which proved to be working as designed.
Nardin dial of 3401 is silvered and uses Roman numerals with all original hands in blued steel
Figure 5. Nardin dial of 3401 is silvered and uses Roman numerals with all original hands in blued steel. Easy to read accurately even under low-light conditions.
Close-up of dial bezel with the inscription in Spanish: “COMISIÓN PARA LA MEDICIÓN DE UN ARCO MERIDIANO LEY 12334”. Translated into English: “COMMISSION FOR THE MEASUREMENT OF A MERIDIAN ARC LAW 12334
Figure 6. Close-up of dial bezel with the inscription in Spanish: “COMISIÓN PARA LA MEDICIÓN DE UN ARCO MERIDIANO LEY 12334”. Translated into English: “COMMISSION FOR THE MEASUREMENT OF A MERIDIAN ARC LAW 12334”.
A 3-tier box made of ribbon-cut Honduran mahogany with brass-bound accents, nameplate, and drop handles
Figure 7. Very attractive 3-tier box made of ribbon-cut Honduran mahogany with brass-bound accents, nameplate, and drop handles.

Geodesy and Meridian Arcs

Geodesy is the scientific discipline that deals with the measurement of the earth.21 Its early beginnings date to antiquity when the earth was thought to be flat. While observing lunar eclipse events, early astronomers noticed that the shadows created on the moon were circular in shape. This indicated that the earth must be spherical in shape. These observers also noticed that as a person traveled south, the North Star, or Polaris, appeared lower in the night sky. Over many years and with intense study, numerous scientists from the entire civilized world focused on determining the shape and size of our planet. While the earth is a sphere or globe, it is not perfectly so shaped and is actually oblate, which means it is flattened at its poles.22

In geodesy, a meridian arc measurement is the distance between two points with the same longitude. This is a segment of a meridian curve or its length. In determining the shape or figure of the earth, two or more of these measurements at different locations are required to calculate what would be the shape of the earth as a sphere. These measurements also involve complex mathematics, including trigonometric calculations and triangulation.23

Latitude and Longitude

I learned in my research that the chronometer was involved in a project that calls for a review of some terminology over and above the title for which the chronometer project was named. As the Argentine military was eventually involved, I think it’s fair to assume the project was more than just an effort to research the shape and size of the earth.

Latitude refers to imaginary lines that circle the earth parallel to the equator, an imaginary circle drawn around the center of the earth designated as 0 degree latitude. These lines determine distance and direction north and south of the equator. There are 90 degrees from the equator to each pole and 60 minutes in each degree.24

A geographic meridian, or line of longitude, refers to imaginary lines that run from pole to pole (north to south) and divide the earth into sections. These lines intersect with lines of latitude and cross at right angles to form a grid. They are equal in length, are halves of great circles, are farthest apart at the equator, and meet at the poles. Meridian lines designate east and west of what is known as the prime meridian. There are 180 degrees west of the prime meridian and 180 degrees east. Longitude is the measurement in degrees of the arc created by an angle drawn from the prime meridian Earth’s axis and then east or west to a meridian.25

The current prime meridian is a line of longitude that was chosen in 1884 at the International Meridian Conference in Washington D.C. as 0 degree longitude, to which all other lines of longitude are designated as east or west. This line is located at the center of the Royal Observatory’s transit instrument room located in Greenwich (near London), England.26

Using a system of latitude measured in degrees and longitude measured in degrees, minutes and seconds at any point on the earth’s surface can be located or positioned with near pinpoint accuracy (Figure 8). To determine longitude, accurate and correct local time is essential, and this requirement is exactly why portable chronometers were developed. As this story takes place in Argentina, we can state the position of Buenos Aires, its capital city, by using the geographical coordinate system: latitude 34 degrees 36’ 47 sec. south, and longitude 58 degrees 22’ 38 sec. west.

An illustration of the earth that shows the relationship between latitude, longitude, the equator, and prime meridian and the grid they form
Figure 8. This graphic is an excellent image that illustrates the relationship between latitude, longitude, the equator, and prime meridian and the grid they form that allows navigators, surveyors, scientists, or anyone to plot the exact location of any coordinate on the earth. BY COURTESY OF ENCYCLOPÆDIA BRITANNICA, INC., COPYRIGHT 2007; USED WITH PERMISSION.

Argentina and Law 12334

On December 21, 1936, a bill for the Measurement of a Meridian Arc in Argentine territory was discussed in the Chamber of Deputies. Sanctioned under law number 12334 (enacted 1937), the intent of this legislation was to meet the “practical needs of the public works”27 as well as research on the shape and dimensions of the earth. A commission was created and a Mr. Felix Aguilar, Director of the Astronomical Observatory of LaPlata, was appointed as its chair. The undertaking was funded and was expected to take 12 years. This confirms the information on the chronometer’s dial bezel and date of manufacture (1939) and also confirms that the instrument was ordered by the Argentine government for this specific project.28

The arc that was to be measured was a distance of 2,734 miles following a line coinciding with the 64 degrees west meridian. This location was chosen as it is close to the transit circle of the Argentine National Observatory near Cordoba (Figure 9). In addition to the astronomical determinations of longitude, latitude and azimuth measurement readings were taken at various points along the Atlantic coast. This project also involved building many mountain towers and affixing marked bronze markers29 (Figure 10).

Work on this law began in 1940, but due to World War II the project lasted longer than the expected 12 years. In 1944, the commission was absorbed by the Military Geographic Institute, which is now named the National Geographic Institute. This undertaking was a great contribution by the Argentine government to define the shape, size, and dimensions of the earth. Much additional knowledge was gained with this project and was important for developing aspects of civil and military interest, particularly in the last half of the 20th century in relation to the navigation systems of ballistic missiles. Today in Argentina, with satellite navigation systems such as Navstar and GLONASS orbiting the earth, this type manual groundwork of measuring and calculating the earth’s surface and features has been deemed obsolete.30

A map with nautical measuremnts
Figure 9. Detail of the measurements made near the 64-degree west meridian in the central area of the Argentine Republic at the National Observatory near Cordova. Note the triangulation measurement points of reference. COURTESY OF LA PLATA ASTRONOMICAL OBSERVATORY, S. PAOLANTONIO.
A bronze medallion of the Astronomical Observatory of the National University of Cordoba
Figure 10. Photo of one of the bronze medallions of the Astronomical Observatory of the National University of Cordoba used in the Meridian Arc Measurement Program. Note the law number 12334 inscribed, the same number that appears on the chronometer’s bezel. COURTESY OF S. PAOLANTONIO.


In the science of geodesy and the mapping of the earth, we discover yet another use for the diversely adaptable portable time keeper—the box or marine chronometer... The marine chronometer was modified in break circuit or survey design that has been admired by many historically prominent horologists. It is probably the single most important timekeeper responsible for the expansion of the civilized world. Land, sea, and celestial navigation; astronomical study of transits and sidereal time; remote exploration of our planet; cartography and survey work on land or at sea—the list of valuable uses seems almost endless. It is impossible to ignore the importance of this instrument and its historical value to the betterment of humanity, and I feel privileged to write about some of its story.

Notes and References

  1. M. Whitney, The Ship’s Chronometer (Cincinnati, OH: American Watchmakers Institute Press, 1985).
  2. Whitney, The Ship’s Chronometer.
  3. See Whitney, The Ship’s Chronometer, and also T. Mercer, Chronometer Makers of the World (London: NAG Press, 1991).
  4. See Whitney, The Ship’s Chronometer, and also Mercer, Chronometer Makers of the World.
  5. Whitney, The Ship’s Chronometer.
  6. Whitney, The Ship’s Chronometer.
  7. See Whitney, The Ship’s Chronometer, and also Mercer, Chronometer Makers of the World.
  8. Mercer, Chronometer Makers of the World.
  9. See Whitney, The Ship’s Chronometer, and also Mercer, Chronometer Makers of the World.
  10. Whitney, The Ship’s Chronometer.
  11. Whitney, The Ship’s Chronometer.
  12. Whitney, The Ship’s Chronometer.
  13. Whitney, The Ship’s Chronometer, 93.
  14. Mercer, Chronometer Makers of the World.
  15. Whitney, The Ship’s Chronometer.
  16. Whitney, The Ship’s Chronometer.
  17. Whitney, The Ship’s Chronometer.
  18. Whitney, The Ship’s Chronometer.
  19. Mercer, Chronometer Makers of the World.
  20. A. R. Clarke, Geodesy (Oxford: Clarendon Press, 1880).
  21. Clarke, Geodesy.
  22. Clarke, Geodesy.
  23. C. Chase, An Introduction to Nautical Science (New York: W. W. Norton and Company, 1991).
  24. Chase, An Introduction to Nautical Science.
  25. National Geographic, “Prime Meridian,” National Geographic Resource Library,
  26. S. Paolantonio, “Contribución Argentina al Conocimiento de la Forma de la Tierra y Dimensiones. Identificación de Algunos Puntos Trigonométricos del Arco de Meridiano Argentino” [English translation: “Argentine Contribution to the Knowledge of the Shape and Dimensions of the Earth: Identification of Some Trigonometric Points of the Argentine Meridian Arc”], Historia de la Astronomía (2015), accessed June 25, 2020,
  27. Paolantonio, “Contribución Argentina al Conocimiento de la Forma de la Tierra y Dimensiones.”
  28. Paolantonio, “Contribución Argentina al Conocimiento de la Forma de la Tierra y Dimensiones.”
  29. Paolantonio, “Contribución Argentina al Conocimiento de la Forma de la Tierra y Dimensiones.”
  30. Paolantonio, “Contribución Argentina al Conocimiento de la Forma de la Tierra y Dimensiones.”


To Jim Haney and the other NAWCC members and readers of this series of “Chronometer Stories” who have shared their positive opinions on my articles and have given me the incentive to continue to write about what I believe to be one of the greatest horological inventions of all time.

A very special thank you to Santiago Paolantonio, Magister Educational Administration History Teaching and Dissemination of Astronomy Area, Cordoba Astronomical Observatory, Argentina, for his positive review and fact checking of the information contained in my research for this story concerning the work done measuring the arc in Argentina. I also appreciate his permission to use his images in this article.

To my good friends and fellow NAWCC members George A. Meyer, my technical guru, and Paul Regan for their continued support and much-appreciated assistance in the preparation of this article. Member Leigh Callaway, our navigational expert, for his review and comments. Sergio Zagier, fellow association member from Argentina, for his assistance in translation. Encyclopædia Britannica, for use of its illustration. A big thank you to our Watch & Clock Bulletin Editor Laura Taylor and the Publications staff for all their help.

About the Author

Burt Cifrulak served as a Staff Sergeant in the United States Air Force and is a Vietnam Veteran. He then spent 30 years with the Allegheny County Police, Pittsburgh, PA, and retired with the rank of Inspector of Police. He published an article in the Watch & Clock Bulletin, with co-author George Meyer, on the Lancaster family of watch companies then turned his attention to the study of marine chronometers and their contributions to science and navigation. This is his seventh article in the marine chronometer series that highlights the makers, their instruments, and the wide variety of uses they performed.

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