History of the metre

2658:

interfering influence of temperature revealed clearly the importance they attached to the expansion-induced errors. It was common knowledge, for instance, that effective measurements were possible only inside a building, the rooms of which were well protected against the changes in outside temperature, and the very presence of the observer created an interference against which it was often necessary to take strict precautions. Thus, the Contracting States also received a collection of thermometers whose accuracy made it possible to ensure that of length measurements. The international prototype would also be a "line standard"; that is, the metre was defined as the distance between two lines marked on the bar, so avoiding the wear problems of end standards.

1057: 1099:– decided that the new measure should be equal to one ten-millionth of the distance from the North Pole to the Equator (the quadrant of the Earth's circumference), measured along the meridian passing through Paris. Apart from the obvious consideration of safe access for French surveyors, the Paris meridian was also a sound choice for scientific reasons: a portion of the quadrant from Dunkirk to Barcelona (about 1000 km, or one-tenth of the total) could be surveyed with start- and end-points at sea level, and that portion was roughly in the middle of the quadrant, where the effects of the Earth's oblateness were expected not to have to be accounted for. The expedition would take place after the 1124: 2244:, while expanding it and making it international. Not, as it was mistakenly assumed for a certain time, that the Association had the unscientific thought of modifying the length of the metre, in order to conform exactly to its historical definition according to the new values that would be found for the terrestrial meridian. But, busy combining the arcs measured in the different countries and connecting the neighbouring triangulations, geodesists encountered, as one of the main difficulties, the unfortunate uncertainty which reigned over the equations of the units of length used. 881: 1723: 1840: 2376: 2748: 1628: 33: 1493: 1208: 1410: 349: 1034: 2288: 2863: 246: 3045: 986: 2449: 5347: 4314: 613: 2689:, and was consecrated as the international prototype metre at the first meeting of the CGPM in 1889. The other bars, duly calibrated against the international prototype, were distributed to the signatory nations of the Metre Convention for use as national standards. For example, the United States received No. 27 with a calibrated length of 1516:, Hassler had brought a standard metre made in Paris to the United States in 1805. He designed a baseline apparatus which instead of bringing different bars in actual contact during measurements, used only one bar calibrated on the metre and optical contact. Thus the metre became the unit of length for geodesy in the United States. 1994:). This territory was covered by a triangle network and included more than thirty observatories or stations whose position was determined astronomically. Bayer proposed to remeasure ten arcs of meridians and a larger number of arcs of parallels, to compare the curvature of the meridian arcs on the two slopes of the 2852:

states, on the contrary, that the mass of a body has an effect on all other bodies while modifying the structure of space. A massive body induces a curvature of the space around it in which the path of light is inflected, as was demonstrated by the displacement of the position of a star observed near

1828:

The definition of the length of a metre in the 1790s was founded upon Arc measurements in France and Peru with a definition that it was to be 1/40 millionth of the circumference of the earth measured through the poles. Such were the inaccuracies of that period that within a matter of just a few years

1463:

was found for the Earth's flattening. However, French astronomers knew from earlier estimates of the Earth's flattening that different meridian arcs could have different lengths and that their curvature could be irregular. The distance from the North Pole to the Equator was then extrapolated from the

3027:

made directly against the international prototype metre; instead, the ratio of the wavelength of the krypton line to that of the cadmium line was determined in vacuum. This was then compared to the 1906 Fabry–Perot determination of the wavelength of the cadmium line in air (with a correction for the

264:

was one of the oldest known units of length. As the name suggests, before the invention of the metre during the French Revolution, many units of length were based on parts of the human body. The oldest known metal length standard corresponds to this Sumerian unit and dates from 2650 BCE. This copper

84:

in 1543. Increasingly accurate measurements were required, and scientists looked for measures that were universal and could be based on natural phenomena rather than royal decree or physical prototypes. Rather than the various complex systems of subdivision then in use, they also preferred a decimal

9059:

This aluminum bar, with an X-shaped cross-section, is a replica of the platinum international meter prototype housed in Paris and used as a standard for the metric system from 1889 to 1960. ... Like an actual meter standard, the bar is 102 centimeters long and there are marks 1 centimeter from each

6595:

Clarke, Alexander Ross (1873), "XIII. Results of the comparisons of the standards of length of England, Austria, Spain, United States, Cape of Good Hope, and of a second Russian standard, made at the Ordnance Survey Office, Southampton. With a preface and notes on the Greek and Egyptian measures of

5533:

4760:

Recueil d'observations géodésiques, astronomiques et physiques, exécutées par ordre du Bureau des longitudes de France, en Espagne, en France, en Angleterre et en Écosse, pour déterminer la variation de la pesanteur et des degrés terrestres sur le prolongement du Méridien de Paris, faisant suite au

2943:

The solution was to define the metre in the same manner as the angstrom had been defined in 1907, that is in terms of the best interferometric wavelength available. Advances in both experimental technique and theory showed that the cadmium line was actually a cluster of closely separated lines, and

2935:

By the 1950s, interferometry had become the method of choice for precise measurements of length, but there remained a practical problem imposed by the system of units used. The natural unit for expressing a length measured by interferometry was the ångström, but this result then had to be converted

2702:

The first (and only) follow-up comparison of the national standards with the international prototype was carried out between 1921 and 1936, and indicated that the definition of the metre was preserved to within 0.2 μm. At this time, it was decided that a more formal definition of the metre was

2492:

In the 1870s and in light of modern precision, a series of international conferences was held to devise new metric standards. When a conflict broke out regarding the presence of impurities in the metre-alloy of 1874, a member of the Preparatory Committee since 1870 and Spanish representative at the

5930:

Recueil d'observations géodésiques, astronomiques et physiques, exécutées par ordre du Bureau des longitudes de France en Espagne, en France, en Angleterre et en Écosse, pour déterminer la variation de la pesanteur et des degrés terrestres sur le prolongement du méridien de Paris... rédigé par MM.

2339:

until 1890. According to geodesists, these standards were secondary standards deduced from the Toise of Peru. In Europe, except Spain, surveyors continued to use measuring instruments calibrated on the Toise of Peru. Among these, the toise of Bessel and the apparatus of Borda were respectively the

941:

resurrected the idea of the seconds pendulum before the Constituent Assembly in 1790, suggesting that the new measure be defined at 45°N (a latitude that, in France, runs just north of Bordeaux and just south of Grenoble): despite the support of the Assembly, nothing came of Talleyrand's proposal.

324:

comprised 7500 Roman feet. The Romans imposed Roman units of measurement throughout their empire. During the Middle Ages, new feet of different lengths appeared in Europe. They all derived more or less directly from the Roman foot. These feet were divided into 12 inches, themselves divided into 12

2657:

For metrology the matter of expansibility was fundamental; as a matter of fact the temperature measuring error related to the length measurement in proportion to the expansibility of the standard and the constantly renewed efforts of metrologists to protect their measuring instruments against the

2456:

In 1867 at the second General Conference of the International Association of Geodesy held in Berlin, the question of an international standard unit of length was discussed in order to combine the measurements made in different countries to determine the size and shape of the Earth. According to a

2461:

the precedent year, the General Conference recommended the adoption of the metre in replacement of the toise of Bessel, the creation of an International Metre Commission, and the foundation of a World institute for the comparison of geodetic standards, the first step towards the creation of the

1969:

by means of gravimetric and leveling measurements, in order to deduce the exact knowledge of the terrestrial spheroid while taking into account local variations. To resolve this problem, it was necessary to carefully study considerable areas of land in all directions. Baeyer developed a plan to

8440:"XIII. Results of the comparisons of the standards of length of England, Austria, Spain, United States, Cape of Good Hope, and of a second Russian standard, made at the Ordnance Survey Office, Southampton. With a preface and notes on the Greek and Egyptian measures of length by Sir Henry James" 5738:"XIII. Results of the comparisons of the standards of length of England, Austria, Spain, United States, Cape of Good Hope, and of a second Russian standard, made at the Ordnance Survey Office, Southampton. With a preface and notes on the Greek and Egyptian measures of length by Sir Henry James" 3731:

At the time the second was defined as a fraction of the Earth's rotation time and determined by clocks whose precision was checked by astronomical observations. In 1936 French and German astronomers found that Earth rotation's speed is irregular. Since 1967 atomic clocks define the second. For

3210:

using any light source of known frequency, rather than defining a "preferred" source in advance. Given that there are more than 22,000 lines in the visible spectrum of iodine, any of which could be potentially used to stabilise a laser source, the advantages of flexibility are obvious.

3100: ≈ 3.39 μm). The krypton line was found to be asymmetrical, so different wavelengths could be found for the laser light depending on which point on the krypton line was taken for reference. The asymmetry also affected the precision to which the wavelengths could be measured. 1829:

more reliable measurements would have given a different value for the definition of this international standard. That does not invalidate the metre in any way but highlights the fact that continuing improvements in instrumentation made better measurements of the earth’s size possible.

2428:

standard had partially been destroyed in 1834, a new standard of reference was constructed using copies of the "Standard Yard, 1760", instead of the pendulum's length as provided for in the Weights and Measures Act of 1824, because the pendulum method proved unreliable. Nevertheless

1115:

would publish in 1821 their observations completing those of Delambre and Mechain. It was an account of the length's variation of the degrees of latitude along the Paris meridian as well as the account of the variation of the seconds pendulum's length along the same meridian between

2275:(IPM) and the arrangement of a system where national standards could be compared with it. The French government gave practical support to the creation of an International Metre Commission, which met in Paris in 1870 and again in 1872 with the participation of about thirty countries. 665:

composed of concentric layers of variable densities. Towards the end of the 18th century, the geodesists sought to reconcile the values of flattening drawn from the measurements of meridian arcs with that given by Clairaut's spheroid drawn from the measurement of gravity. In 1789,

2654:" (For all times, to all peoples); and this deed consisted in the approval and distribution, among the governments of the states supporting the Metre Convention, of prototype standards of hitherto unknown precision intended to propagate the metric unit throughout the whole world. 8765:"Bericht der schweizerischen Delegierten an der internationalen Meterkonferenz an den Bundespräsidenten und Vorsteher des Politischen Departements, J. J. Scherer in Erwin Bucher, Peter Stalder (ed.), Diplomatic Documents of Switzerland, vol. 3, doc. 66, dodis.ch/42045, Bern 1986" 2348:. These measuring devices consisted of bimetallic rulers in platinum and brass or iron and zinc fixed together at one extremity to assess the variations in length produced by any change in temperature. The combination of two bars made of two different metals allowed to take 8090:"Appareil construit pour les opérations au moyen desquelles on prolongera dans toute l'étendue de l'Espagne le réseau trigonométrique qui couvre la France in Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels" 5446:"Appareil construit pour les opérations au moyen desquelles on prolongera dans toute l'étendue de l'Espagne le réseau trigonométrique qui couvre la France in Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels" 3146:

Nevertheless, the infrared light from a methane-stabilised laser was inconvenient for use in practical interferometry. It was not until 1983 that the chain of frequency measurements reached the 633 nm line of the helium–neon laser, stabilised using molecular

2621:, delegate of Switzerland at this Diplomatic Conference in 1875, conformed to the opinion of Italy and Spain to create, in spite of French reluctance, the International Bureau of Weights and Measures in France as a permanent institution at the disadvantage of the 9371:"Détermination de la valeur en Ångströms de la longeur d'onde de la raie rouge du Cadmium considérée comme étalon primaire" [Determination of the value in Ångströms of the wavelength of the red line of cadmium under consideration as a primary standard]. 1813:'s model. However, the following year, resuming his calculation on the basis of all the data available at the time, Ritter came to the conclusion that the problem was only resolved in an approximate manner, the data appearing too scant, and for some affected by 3988:

The term "prototype" does not imply that it was the first in a series and that other standard metres would come after it: the "prototype" metre was the one that came first in the logical chain of comparisons, that is the metre to which all other standards were

2531:, France. This new organisation was to construct and preserve a prototype metre bar, distribute national metric prototypes, and maintain comparisons between them and non-metric measurement standards. The organisation distributed such bars in 1889 at the first 1851:, Méchain had found that the difference between these latitudes was greater than predicted by direct measurement of distance by triangulation and that he did not dare to admit this inaccuracy. This was later explained by clearance in the central axis of the 2405:. If precision metrology had needed the help of geodesy, the latter could not continue to prosper without the help of metrology. It was then necessary to define a single unit to express all the measurements of terrestrial arcs and all determinations of the 1479:. When the final result was known, a bar whose length was closest to the meridional definition of the metre was selected and placed in the National Archives on 22 June 1799 (4 messidor An VII in the Republican calendar) as a permanent record of the result. 3108:. Although visible and infrared frequencies were still too high to be directly measured, it was possible to construct a "chain" of laser frequencies that, by suitable multiplication, differ from each other by only a directly measurable frequency in the 1682:

in Paris. Ismail Mustafa had the task to carry out the experiments necessary for determining the expansion coefficients of the two platinum and brass bars, and to compare the Egyptian standard with a known standard. The Spanish standard designed by

9715:

Pollock, C. R.; Jennings, D. A.; Petersen, F. R.; Wells, J. S.; Drullinger, R. E.; Beaty, E. C.; Evenson, K. M. (1983). "Direct frequency measurements of transitions at 520 THz (576 nm) in iodine and 260 THz (1.15 μm) in neon".

2577:, Carlos Ibáñez e Ibáñez de Ibero had been elected president. His presidency was confirmed at the first meeting of the International Committee for Weights and Measures, on 19 April 1875. Three other members of the committee, the German astronomer, 1413:

A copy of the "provisional" metre installed 1796–1797, located in the wall of a building, 36 rue de Vaugirard, Paris. These metres were based on the "provisional" metre, because the expedition to re-determine the metre was not completed until

555:. Picard's geodetic observations had been confined to the determination of the magnitude of the earth considered as a sphere, but the discovery made by Jean Richer turned the attention of mathematicians to its deviation from a spherical form. 2647:

In 1889 the General Conference on Weights and Measures met at Sèvres, the seat of the International Bureau. It performed the first great deed dictated by the motto inscribed in the pediment of the splendid edifice that is the metric system:

966:

in the United Kingdom. More precisely, it was decided in 1824 that if the genuine standard of the yard was lost, it could be restored by reference to the length of a pendulum vibrating seconds at London. However, when the primary Imperial

1570:

and gravity in different points of the globe stimulated the creation of the first international scientific associations. The foundation of the Magnetischer Verein would be followed by that of the Central European Arc Measurement (German:

2327:, was the French primary standard of the toise, and the metre was officially defined by an artifact made of platinum kept in the National Archives. Besides the latter, another platinum and twelve iron standards of the metre were made by 6880:

Nouvelle détermination de la distance méridienne de Montjouy à Formentera, dévoilant l'inexactitude de celle dont il est fait mention dans la base du système métrique décimal, par M. Puissant,... lu à l'Académie des sciences, le 2 mai

951: 5777:

Clarke, Alexander Ross (1 January 1867). "X. Abstract of the results of the comparisons of the standards of length of England, France, Belgium, Prussia, Russia, India, Australia, made at the ordnance Survey Office, Southampton".

2948:

in natural cadmium (eight in total). To get the most precisely defined line, it was necessary to use a monoisotopic source and this source should contain an isotope with even numbers of protons and neutrons (so as to have zero

1695:'s double-toise N° 1, which served as a comparison module for the measurement of all geodesic bases in France, and was also to be compared to the Ibáñez apparatus. In 1954, the connection of the southerly extension of the 1789:. This did not pave the way to a new definition of the metre because it was known that the theoretical definition of the metre had been inaccessible and misleading at the time of Delambre and Mechain arc measurement, as the 186:

of the new prototypes of the metre and their comparison with each other and with the historical standard involved the development of specialized measuring equipment and the definition of a reproducible temperature scale.

2723:, this bar being subject to standard atmospheric pressure and supported on two cylinders of at least one centimetre diameter, symmetrically placed in the same horizontal plane at a distance of 571 mm from each other. 2240:, founded to combine the geodetic operations of different countries, in order to reach a new and more exact determination of the shape and dimensions of the Globe, prompted the project of reforming the foundations of the 936:

of 1789. France was particularly affected by the proliferation of length measures, and the need for reform was widely accepted across all political viewpoints, even if it needed the push of revolution to bring it about.

971:

standard was partially destroyed in 1834, a new standard of reference was constructed using copies of the "Standard Yard, 1760" instead of the pendulum's length as provided for in the Weights and Measures Act of 1824.

2388:

would mark the adoption of new scientific methods. It then became possible to accurately measure parallel arcs, since the difference in longitude between their ends could be determined thanks to the invention of the

1730:, through Great Britain, France and Spain to El Aghuat in Algeria, whose parameters were calculated from surveys carried out in the mid to late 19th century. It yielded a value for the equatorial radius of the earth 1474:

toises. As the metre had to be equal to one ten-millionth of this distance, it was defined as 0.513074 toise or 3 feet and 11.296 lines of the Toise of Peru, which had been constructed in 1735 for the

1188:, and took more than six years (1792–1798). The technical difficulties were not the only problems the surveyors had to face in the convulsed period of the aftermath of the Revolution: Méchain and Delambre, and later 1442:

between these two towns and determined the portion of the distance from the North Pole to the Equator it represented. Pierre Méchain's and Jean-Baptiste Delambre's measurements were combined with the results of the

1661:

an Observatory which he was keen to keep in harmony with the progress of this science still in progress. In 1858, a Technical Commission was set up to continue, by adopting the procedures instituted in Europe, the

3103:

Developments in electronics also made it possible for the first time to measure the frequency of light in or near the visible region of the spectrum, instead of inferring the frequency from the wavelength and the

2256:

decided, in order to make all the standards comparable, to propose to the Association to choose the metre for geodetic unit, and to create an international prototype metre differing as little as possible from the

9563:

Evenson, K. M.; Wells, J. S.; Petersen, F. R.; Danielson, B. L.; Day, G. W.; Barger, R. L.; Hall, J. L. (1972). "Speed of Light from Direct Frequency and Wavelength Measurements of the Methane-Stabilized Laser".

3201:

The concept of defining a unit of length in terms of a time received some comment. In both cases, the practical issue is that time can be measured more accurately than length (one part in 10 for a second using a

2485:, whose theorem has long supported the assumption of an ellipsoid with three unequal axes for the figure of the Earth, inviting his French counterpart to undertake joint action to ensure the universal use of the 2379:

Historic Dutch replicas of metric standards in the collection of Rijksmuseum, Amsterdam: iron metre with case constructed by Étienne Lenoir in 1799, copper grave kilogram with case (1798), copper volume measures

6504:

Base du système métrique décimal, ou Mesure de l'arc du méridien compris entre les parallèles de Dunkerque et Barcelone. T. 1 /, exécutée en 1792 et années suivantes, par MM. Méchain et Delambre, rédigée par M.

5222:

7405:

Dictionnaire des inventions et découvertes anciennes et modernes, dans les sciences, les arts et l'industrie.... 2. H–Z / recueillis et mis en ordre par M. le marquis de Jouffroy; publié par l'abbé Migne,...

3628: 2703:

required (the 1889 decision had said merely that the "prototype, at the temperature of melting ice, shall henceforth represent the metric unit of length"), and this was agreed at the 7th CGPM in 1927.

104:(a pendulum with a half-period of one second) one century earlier, but this was rejected as it had been discovered that this length varied from place to place with local gravity. A new unit of length, the 1734:= 6 377 935 metres, the ellipticity being assumed as 1/299.15. The radius of curvature of this arc is not uniform, being, in the mean, about 600 metres greater in the northern than in the southern part. 9352: 5381: 2661:

The construction of the international prototype metre and the copies which were the national standards was at the limits of the technology of the time. The bars were made of a special alloy, 90%

3081:, of which the first working version was constructed in the same year as the redefinition of the metre. Laser light is usually highly monochromatic, and is also coherent (all the light has the same 2735:

under its own weight. Because the prototype is a line standard, its full length is 102 cm, slightly longer than 1 metre. Cross-sectionally, it measures 16 mm × 16 mm.

190:

Progress in science finally allowed the definition of the metre to be dematerialized; thus in 1960 a new definition based on a specific number of wavelengths of light from a specific transition in

3523: 2755:

The comparison of the new prototypes of the metre with each other involved the development of special measuring equipment and the definition of a reproducible temperature scale. The BIPM's

1149:", a surveying instrument which allowed a much-improved precision in the measurement of angles between landmarks, but insisted that two different version of the device be calibrated one in 4338:"Article Pié, (Mesure de longueur.), vol. XII (1765), p. 562a–463 [563]b Enccre/ICE - Interface de Consultation de l'Édition numérique collaborative et critique de l'Encyclopédie" 3935: 6308:"X. Abstract of the results of the comparisons of the standards of length of England, France, Belgium, Prussia, Russia, India, Australia, made at the ordnance Survey Office, Southampton" 1120:

and the Baleares. Improvements in the measuring devices designed by Borda and used for this survey also raised hopes for a more accurate determination of the length of this meridian arc.

4363:"Article Mesure longue, (Antiq. Arts & Comm.), vol. X (1765), p. 411b–418a Enccre/ICE - Interface de Consultation de l'Édition numérique collaborative et critique de l'Encyclopédie" 1196:, which he contracted while trying to improve his original results in northern Spain. In the meantime, the commission calculated a provisional value from older surveys of 443.44 3720: 3679: 7826: 5561: 533:

of 9.5 arcseconds, equivalent to an Earth–Sun distance of about 22,000 Earth radii. They were also the first astronomers to have access to an accurate and reliable value for the

3850: 5377:"Rapport de M. Faye sur un Mémoire de M. Peirce concernant la constance de la pesanteur à Paris et les corrections exigées par les anciennes déterminations de Borda et de Biot" 1749:, some of the meridian arcs the German astronomer had used for his calculation had been enlarged. This was a very important circumstance because the influence of errors due to 3891: 9031: 7896:

Recherche des coefficients de dilatation et étalonnage de l'appareil à mesurer les bases géodésiques appartenant au gouvernement égyptien / par Ismaïl-Effendi-Moustapha, ...

7035:

Recherche des coefficients de dilatation et étalonnage de l'appareil à mesurer les bases géodésiques appartenant au gouvernement égyptien / par Ismaïl-Effendi-Moustapha, ...

1965:

Baeyer's goal was a new determination of anomalies in the shape of the Earth using precise triangulations, combined with gravity measurements. This involved determining the

4514:

Le système métrique des poids et mesures; son établissement et sa propagation graduelle, avec l'histoire des opérations qui ont servi à déterminer le mètre et le kilogramme

9769:

Jennings, D. A.; Pollock, C. R.; Petersen, F. R.; Drullinger, R. E.; Evenson, K. M.; Wells, J. S.; Hall, J. L.; Layer, H. P. (1983). "Direct frequency measurement of the I

6065:

Jean-Jacques Levallois, La méridienne de Dunkerque à Barcelone et la détermination du mètre (1792 – 1799), Vermessung, Photogrammetrie, Kulturtechnik, 89 (1991), 375-380.

2763:, whose practically negligible coefficient of expansion made it possible to develop simpler baseline measurement methods, and for which its director, the Swiss physicist 9409: 3783: 464: 97: 8058: 8578:

Dodis, Diplomatische Dokumente der Schweiz | Documents diplomatiques suisses | Documenti diplomatici svizzeri | Diplomatic Documents of Switzerland | (30 March 1875),

5494:

Le général Ibáñez notice nécrologique lue au comité international des poids et mesures, le 12 septembre et dans la conférence géodésique de Florence, le 8 octobre 1891

865:

of 1875, when the metre was adopted as an international scientific unit of length for the convenience of continental European geodesists following forerunners such as

4075: 3558: 1297:

End of November 1798, Delambre and Méchain returned to Paris with their data, having completed the survey to meet a foreign commission composed of representatives of

4220:"Du pied au mètredu marc au kiloL'histoire des unités des poids et mesuresévoquée par quelques objets emblématiques descollections du Musée d'histoire des sciences" 3135:

values for the speed of light, depending on which point on the krypton line was chosen to define the metre. This ambiguity was resolved in 1975, when the 15th

1519:

In 1830, Hassler became head of the Office of Weights and Measures, which became a part of the Survey of the Coast. He compared various units of length used in the

9646:

Evenson, K. M.; Day, G. W.; Wells, J. S.; Mullen, L. O. (1972). "Extension of Absolute Frequency Measurements to the cw He☒Ne Laser at 88 THz (3.39 μ)".

6939:"Über einen Fehler in der Berechnung der französischen Gradmessung und seineh Einfluß auf die Bestimmung der Figur der Erde. Von Herrn Geh. Rath und Ritter Bessel" 2505:

to rally France to the project to create an International Bureau of Weights and Measures equipped with the scientific means necessary to redefine the units of the

2609:

along with the Russian and Austrian representatives boycotted the Permanent Committee of the International Metre Commission in order to prompt the reunion of the

503:

meaning universal measure for this unit of length, but then it was discovered that the length of a seconds pendulum varies from place to place: French astronomer

8584:(in French), Diplomatische Dokumente der Schweiz | Documents diplomatiques suisses | Documenti diplomatici svizzeri | Diplomatic Documents of Switzerland | Dodis 1691:

was chosen for this purpose, as it had served as a model for the construction of the Egyptian standard. In addition, the Spanish standard had been compared with

8581:

Bericht der schweizerischen Delegierten an der internationalen Meterkonferenz an den Bundespräsidenten und Vorsteher des Politischen Departements, J. J. Scherer

2433:'s use of the metre and the creation of the Office of Standard Weights and Measures as an office within the Coast Survey contributed to the introduction of the 2040:

hesitated for a long time before giving in to the demands of the Association, which asked the French geodesists to take part in its work. It was only after the

6446:"Les origines du système métrique en France et la Convention du mètre de 1875, qui a ouvert la voie au Système international d'unités et à sa révision de 2018" 5585:"Les origines du système métrique en France et la Convention du mètre de 1875, qui a ouvert la voie au Système international d'unités et à sa révision de 2018" 2677:) to minimise the effects of torsional strain during length comparisons. The first castings proved unsatisfactory, and the job was given to the London firm of 6375:

Grand dictionnaire universel du XIXe siècle : français, historique, géographique, mythologique, bibliographique.... T. 11 MEMO-O / par M. Pierre Larousse

5508:"Histoire de l'appareil Ibañez-Brunner in Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels" 2936:

into metres using an experimental conversion factor – the wavelength of light used, but measured in metres rather than in ångströms. This added an additional

2907: 2707:

The unit of length is the metre, defined by the distance, at 0°, between the axes of the two central lines marked on the bar of platinum–iridium kept at the

7364:

Martina Schiavon. La geodesia y la investigación científica en la Francia del siglo XIX : la medida del arco de meridiano franco-argelino (1870–1895).

2437:

allowing the use of the metre in the United States, and preceded the choice of the metre as international scientific unit of length and the proposal by the

1024: 3077:(63.14 K, −210.01 °C) was the state-of-the-art light source for interferometry in 1960, but it was soon to be superseded by a new invention: the 9073: 2597:

representing Russia, and the Swiss geodesist of German origin, Adolphe Hirsch were also among the main architects of the Metre Convention. In the 1870s,

1797:, but which in detail differs from it so as to prohibit any generalization and any extrapolation from the measurement of a single meridian arc. In 1859, 4712: 3754: 2416:, might be so much damaged that comparison with it would be worthless, while Bessel had questioned the accuracy of copies of this standard belonging to 2295:

and given to the United States, which served as the standard for American cartography from 1890 replacing the Committee Meter, an authentic copy of the

746:

and the data of the meridian arc of Delambre and Méchain. This value was the result of a conjecture based on too limited data. Thus the results of the

9106: 4105: 6914:

Struve Geodetic Arc, 2006 International Conference, The Struve Arc and Extensions in Space and Time, Haparanda and Pajala, Sweden, 13–15 August 2006

5284:

Struve Geodetic Arc, 2006 International Conference, The Struve Arc and Extensions in Space and Time, Haparanda and Pajala, Sweden, 13–15 August 2006

4219: 4023: μm; taking the intensity-weighted mean point ("centre of gravity") of the krypton line as the standard, the wavelength of the methane line is 4459: 2570: 1594: 7828:

Bericht über die Verhandlungen der vom 30. September bis 7. October 1867 zu BERLIN abgehaltenen allgemeinen Conferenz der Europäischen Gradmessung

5563:

Bericht über die Verhandlungen der vom 30. September bis 7. October 1867 zu BERLIN abgehaltenen allgemeinen Conferenz der Europäischen Gradmessung

2638: 2452:

Creating the metre-alloy in 1874 at the Conservatoire des Arts et Métiers. Present Henri Tresca, George Matthey, Saint-Claire Deville, and Debray.

7909: 7879: 7450: 7419: 7048: 7018: 6895: 6863: 6519: 6276: 5945: 5237: 4463: 8880: 6812: 5704:[The measure of Paris] (in French). Laboratoire de Médiévistique Occidentale de Paris – via Sciences de l'Homme et de la Société. 2154: 1547: 4321: 2291:

Closeup of National Prototype Metre Bar No. 27, made in 1889 by the International Bureau of Weights and Measures (BIPM) in collaboration with

2022:

could open the field to scientific research of the highest interest, research that each State, taken in isolation, was not able to undertake.

1894:

with the aim of determining the shape and dimensions of the Earth. At the time of its creation, the association had sixteen member countries:

8971: 8662:

Torge, W. (1 April 2005). "The International Association of Geodesy 1862 to 1922: from a regional project to an international organization".

6624: 1103:, thus the French meridian arc, which would extend northwards across the United Kingdom, would also extend southwards to Barcelona, later to 2622: 9701: 8948: 8617: 7951:

Comptes-rendus des séances de la Commission permanente de l'Association géodésique internationale réunie à Florence du 8 au 17 octobre 1891

7192:

Comptes-rendus des séances de la Commission permanente de l'Association géodésique internationale réunie à Florence du 8 au 17 octobre 1891

6704: 2681:

who succeeded in producing thirty bars to the required specification. One of these, No. 6, was determined to be identical in length to the

2614: 2566: 2463: 2424:

Observatories, which he had compared to each other about 1840. This assertion was particularly worrying, because when the primary Imperial

7576:"From a Regional Project to an International Organization: The "Baeyer-Helmert-Era" of the International Association of Geodesy 1862–1916" 1678:

the study, in Europe, of the precision apparatus calibrated against the metre intended to measure the geodesic bases and already built by

1485: 9906: 8784:"Wilhelm Foerster's Role in the Metre Convention of 1875 and in the Early Years of the International Committee for Weights and Measures" 8527: 8154:

Discursos leidos ante la Real Academia de Ciencias Exactas Fisicas y Naturales en la recepcion pública de Don Joaquin Barraquer y Rovira

7713:"Wilhelm Foerster's Role in the Metre Convention of 1875 and in the Early Years of the International Committee for Weights and Measures" 7304:"Figure de la Terre, in Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, par une Société de Gens de lettres" 5359:

Discursos leidos ante la Real Academia de Ciencias Exactas Fisicas y Naturales en la recepcion pública de Don Joaquin Barraquer y Rovira

5081: 4948: 3151:. That same year, the 17th CGPM adopted a definition of the metre, in terms of the 1975 conventional value for the speed of light: 2634:, just outside Paris. However, as an international organisation, the BIPM is under the ultimate control of a diplomatic conference, the 9697: 2574: 2532: 2217:

which was a prerequisit for both military operations and the creation of the infrastructures needed for industrial development such as

1770: 8558:"Carlos Ibáñez e Ibáñez de Ibero (14 avril 1825 – 29 janvier 1891), par Albert Pérard (inauguration d'un monument élevé à sa mémoire)" 5473:"Carlos Ibáñez e Ibáñez de Ibero (14 avril 1825 – 29 janvier 1891), par Albert Pérard (inauguration d'un monument élevé à sa mémoire)" 4176: 3564: 3206:

as opposed to four parts in 10 for the metre in 1983). The definition in terms of the speed of light also means that the metre can be

2498: 2253: 1762: 1684: 1582: 874: 7436:

Grandeur et figure de la terre / J.-B.-J. Delambre; ouvrage augmenté de notes, de cartes et publié par les soins de G. Bigourdan,...

6263:

Grandeur et figure de la terre / J.-B.-J. Delambre; ouvrage augmenté de notes, de cartes et publié par les soins de G. Bigourdan,...

2731:

of the prototype—the support points, separated by 0.5594 of the total length of the bar, that minimise shortening of the bar due to

1358: 938: 809:

Significant improvements in gravity measuring instruments must also be attributed to Bessel. He devised a gravimeter constructed by

908: 406: 9224: 3173:

The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum

2336: 2150: 1509: 338: 330: 1753:

was minimized in proportion to the length of the meridian arcs: the longer the meridian arcs, the more precise the image of the

1612:

declared to the French Academy of Sciences in 1836 that Jean Baptiste Joseph Delambre and Pierre Méchain had made errors in the

999: 2807: 2413: 1476: 1444: 767: 743: 598: 5309:"Ueber einen Fehler in der Berechnung der französischen Gradmessung und seinen Einfluss auf die Bestimmung der Figur der Erde" 2573:. At the session on 12 October 1872 of the Permanent Committee of the International Metre Commission, which was to become the 1558:, second). In 1836, he founded the Magnetischer Verein, the first international scientific association, in collaboration with 194:

allowed the standard to be universally available by measurement. In 1983 this was updated to a length defined in terms of the

9876: 9261: 8066: 7959: 7932: 7599: 7200: 6788: 6680: 6024: 5420: 5105: 5013: 1962:

created a Central Office, located at the Prussian Geodetic Institute, whose management was entrusted to Johann Jacob Baeyer.

1871:

also had an impact on accuracy of latitudes' determinations. Among all these sources of error, it was mainly an unfavourable

9400:

Hollberg, L.; Oates, C. W.; Wilpers, G.; Hoyt, C. W.; Barber, Z. W.; Diddams, S. A.; Oskay, W. H.; Bergquist, J. C. (2005).

8008:

Recherches historiques sur les étalons de poids et mesures de l'observatoire et les appareils qui ont servi a les construire

7219: 6762:

in COMlTÉ INTERNATIONAL DES POIDS ET MESURES. PROCÈS-VERBAUX DES SÉANCES. DEUXIÈME SÉRIE. TOME II. SESSION DE 1903. pp. 5–7.

2086:

in 1898. The convention of the International Geodetic Association expired at the end of 1916. It was not renewed due to the

9050: 4083: 3420: 2602: 2438: 2385: 2266: 2237: 2033: 1959: 1766: 1573: 1273: 803: 402: 175: 8385: 2328: 1135: 4824: 3131:

almost 100 times lower than previous measurements in the microwave region. Or, somewhat inconveniently, the results gave

1821:

in the French meridian arc which determination had also been affected in a lesser proportion by systematic errors of the

1342: 1100: 896: 885: 379:

explaining the fall of bodies at the surface of the Earth. He also observed the regularity of the period of swing of the

79: 8874: 3484: 7345:

Société de physique et d'histoire naturelle de Genève.; Genève, Société de physique et d'histoire naturelle de (1861).

7328:

Société de physique et d'histoire naturelle de Genève.; Genève, Société de physique et d'histoire naturelle de (1859).

6244: 2849: 2357: 2162: 747: 602: 297: 278: 2412:

In 1866, the most important concern was that the Toise of Peru, the standard of the toise constructed in 1735 for the

1256:. In an operation taking six weeks, the baseline was accurately measured using four platinum rods, each of length two 8965: 8473:"Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels" 8356: 7865:

Notes biographiques de S. E. Mahmoud Pacha el Falaki (l'astronome), par Ismail-Bey Moustapha et le colonel Moktar-Bey

7151:"Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels" 7004:

Notes biographiques de S. E. Mahmoud Pacha el Falaki (l'astronome), par Ismail-Bey Moustapha et le colonel Moktar-Bey

6219: 5643: 5253:"Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels" 4800: 4598: 4435: 4402: 233:

Where older traditional length measures are still used, they are now defined in terms of the metre – for example the

3088:

The shortcomings of the krypton standard were demonstrated by the measurement of the wavelength of the light from a

1079:. Instead of the seconds pendulum method, the commission of the French Academy of Sciences – whose members included 774:

would calculate the Earth's flattening from ten meridian arcs measured with sufficient accuracy using the method of

3999: 2848:, infinite and without boundaries and bodies gravitated around each other without changing the structure of space. 1326: 569:

length was a means to measure gravitational acceleration. In the 18th century, in addition to its significance for

8713: 8239: 5847: 1809:, using Schubert's data computed that the Earth ellipsoid could rather be a spheroid of revolution accordingly to 1616:, which had been used to determine the length of the metre. Errors in the method of calculating the length of the 1042: 155:, particularly in scientific usage, and it was officially established as an international measurement unit by the 9929: 9319:; Benoît, Jean-René (1895). "Détermination expérimentale de la valeur du mètre en longueurs d'ondes lumineuses". 7303: 7086:"A profile of General Carlos Ibáñez e Ibáñez de Ibero: first president of the International Geodetic Association" 6041: 4708: 4643: 2795: 1951: 17: 1879:

and a metre "too short" compared to a more general definition taken from the average of a large number of arcs.

9077: 6416: 4541: 2091: 1350: 1346: 1056: 148: 6501:

Delambre, Jean-Baptiste (1749–1822) Auteur du texte; Méchain, Pierre (1744–1804) Auteur du texte (1806–1810).

5219:

Delambre, Jean-Baptiste (1749-1822) Auteur du texte; Méchain, Pierre (1744-1804) Auteur du texte (1806–1810).

4337: 1228: 670:

obtained by a calculation taking into account the measures of meridian arcs known at the time a flattening of

653:

synthesized the relationships existing between gravity and the shape of the Earth. Clairaut exposed there his

4723: 4362: 3684: 3635: 3257: 2545: 2361: 333:

each. Multiples of these feet became the length standards in various European cities. For example, the Paris

9114: 9033:

The International Bureau of Weights and Measures, 1875-1975 : translation of the BIPM centennial volume

4876: 4113: 2968:

both fulfil the condition of zero nuclear spin and have bright lines in the visible region of the spectrum.

2213:

would challenge Britain as the foremost industrial nation in Europe. This was accompanied by development in

1366: 565:

which explained variations of gravitational acceleration depending on latitude. He also discovered that the

9601:

Barger, R. L.; Hall, J. L. (1973). "Wavelength of the 3.39-μm laser-saturated absorption line of methane".

8611: 2206: 2101: 1671: 1072: 904: 552: 274: 160: 3119:

Independent measurements of frequency and wavelength are, in effect, a measurement of the speed of light (

2940:

to any length result in metres, over and above the uncertainty of the actual interferometric measurement.

2764: 108:

was introduced – defined as one ten-millionth of the shortest distance from the North Pole to the equator

9869: 8545:

National Institute of Standards and Technology 2003; Historical context of the SI: Unit of length (meter)

8166: 5376: 2470: 1370: 1219:

The project was split into two parts – the northern section of 742.7 km from the belfry, Dunkirk to

5902: 4019:

Taking the point of highest intensity as the reference wavelength, the methane line had a wavelength of

3334:

Platinum-iridium bar at melting point of ice, atmospheric pressure, supported by two rollers (7th CGPM)

2519:) of 1875 mandated the establishment of a permanent International Bureau of Weights and Measures (BIPM: 2205:

in 1871. Meanwhile most European countries had adopted the metre. The 1870s marked the beginning of the

2060:

was appointed member of the Permanent Commission which was presided by Carlos Ibáñez e Ibáñez de Ibero.

1390: 202:

The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the

9452: 3292: 3053: 2502: 2406: 1802: 1735: 384: 376: 2045: 8637: 8413: 5927:

Biot, Jean-Baptiste (1774-1862) Auteur du texte; Arago, François (1786-1853) Auteur du texte (1821).

2740: 2430: 2300: 1535: 1505: 1439: 1251: 1004: 866: 586: 518: 418: 410: 249: 8848: 8521: 7110: 6922: 5722: 5292: 5279: 5075: 4942: 2605:

but its overwhelming influence was mitigated by that of neutral states. While the German astronomer

2225:, geodesists called for the creation of a "European international bureau for weights and measures". 1805:. He also proposed an ellipsoid with three unequal axes. In 1860, Elie Ritter, a mathematician from 649:('Theory of the Figure of the Earth, drawn from the Principles of Hydrostatics') published in 1743, 7284:, Allgemeine Deutsche Biographie (1. ed.), München/Leipzig: Duncker & Humblot, p. 231 3127:), and the results from the methane-stabilised laser gave the value for the speed of light with an 2669:, which was significantly harder than pure platinum, and have a special X-shaped cross section (a " 1675: 1674:

was in charge, in Egypt, of the direction of the work of the general map, the viceroy entrusted to

1566:. The coordination of the observation of geophysical phenomena such as the Earth's magnetic field, 1438:

and Jean-Baptiste Delambre calculated the distance from Dunkirk to Barcelona using the data of the

932:, little practical advance was made towards the establishment of the "universal measure" until the 838: 799: 203: 8952: 7378: 7275: 3011: wavelengths in vacuum of the radiation corresponding to the transition between the levels 2p 1028: 9648: 9603: 9566: 9347: 6157: 5591:. The new International System of Units / Le nouveau Système international d’unités (in French). 4276:

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

4268: 4237: 3207: 3128: 2937: 2756: 2606: 2578: 2474: 2421: 1688: 667: 620: 593:

was the unit to which all celestial distances were to be referred. Indeed, Earth proved to be an

582: 8557: 7344: 7327: 6712: 6307: 6110: 5633: 5472: 2469:

Hassler's metrological and geodetic work also had a favourable response in Russia. In 1869, the

1123: 413:. They both also used a determination of the size of the Earth, then considered as a sphere, by 8193:"Über das preufs. Längenmaaß und die zu seiner Verbreitung durch Copien ergriffenen Maaßregeln" 7105: 6917: 5308: 5287: 4480:

The Elements of Commerce; or, a treatise on different calculations,-operations of exchange, etc

2929: 2768: 2280: 2222: 2202: 1798: 1559: 1431: 1306: 1185: 822: 9840: 9251: 8730: 8042: 7949: 7190: 4670: 4478: 3187:

when expressed in the unit m⋅s, where the second is defined in terms of the caesium frequency

3085:, unlike the light from a discharge lamp), both of which are advantageous for interferometry. 2323:

were the legal basis of units of length. A wrought iron ruler, the Toise of Peru, also called

219:

when expressed in the unit m⋅s, where the second is defined in terms of the caesium frequency

9900: 6180: 5709: 3528: 3093: 3049: 2879: 2365: 1931: 1810: 1692: 1650: 1435: 1382: 1362: 1131: 1084: 1080: 1076: 707: 654: 364: 69: 4906: 4758: 4569: 174:

and its copies such as the Committee Meter were replaced from 1889 at the initiative of the

169: 138: 9784: 9727: 9657: 9612: 9575: 9526: 9489: 9418: 9380: 9148: 9004: 8919: 8910: 8795: 8671: 8310: 8271: 8204: 7781: 7724: 7628: 7244:

Vermessung, Photogrammetrie, Kulturtechnik: VPK = Mensuration, Photogrammétrie, Génie Rural

7097: 6950: 6566: 6457: 5876: 5596: 5357: 5194: 4629: 4193: 3253: 3155:

The metre is the length of the path travelled by light in vacuum during a time interval of

2390: 2312: 2194: 2037: 1975: 1907: 1605: 1563: 1531: 1427: 1386: 1334: 1096: 1088: 870: 492: 135:

The historical French official standard of the metre was made available in the form of the

53: 6625:"A Tale About the First Weights and Measures Intercomparison in the United States in 1832" 1464:

measurement of the Paris meridian arc between Dunkirk and Barcelona and was determined as

962:

as a length standard did not die completely, and such a definition was used to define the

8: 9316: 7834:(in German). Berlin: Central-Bureau der Europäischen Gradmessung. 1868. pp. 123–134. 7575: 6780:

From artefacts to atoms : the BIPM and the search for ultimate measurement standards

6533:

American Philosophical Society.; Society, American Philosophical; Poupard, James (1825).

6390: 5960: 5821: 5569:(in German). Berlin: Central-Bureau der Europäischen Gradmessung. 1868. pp. 123–134. 4184: 2977: 2875: 2799: 2353: 2308: 2249: 2198: 2190: 2146: 2041: 1999: 1883: 1872: 1868: 1814: 1801:

demonstrated that several meridians had not the same length, confirming an hypothesis of

1758: 1750: 1696: 1578: 1378: 1269: 994: 830: 632: 144: 73: 9788: 9731: 9661: 9616: 9579: 9530: 9493: 9422: 9384: 9152: 9008: 8923: 8799: 8675: 8314: 8275: 8259: 8208: 8192: 7785: 7728: 7632: 7101: 6954: 6938: 6570: 6461: 5880: 5864: 5600: 5198: 5121: 4518: 4197: 9862: 9751: 9673: 9628: 9542: 9434: 9209: 9174: 8695: 8334: 7978: 7903: 7873: 7805: 7750: 7652: 7526: 7444: 7413: 7131: 7042: 7012: 6889: 6857: 6806: 6649: 6513: 6483: 6327: 6270: 6138: 5939: 5803: 5231: 5163: 4984: 4750: 4453: 3415: 3410: 3064: 2981: 2845: 2837: 2825: 2582: 2434: 2417: 2369: 2178: 2166: 2109: 2105: 1923: 1915: 1911: 1834:

Nomination of the STRUVE GEODETIC ARC for inscription on the WORLD HERITAGE LIST, p. 40

1646: 1318: 1314: 1310: 1108: 929: 892: 558: 7846: 7062: 6985: 6827: 5701: 5038: 2352:

into account without measuring the temperature. A French scientific instrument maker,

2062:

The International Geodetic Association gained global importance with the accession of

1060: 798:

would long be used by geodesists. An even more accurate value was proposed in 1901 by

9872: 9800: 9743: 9677: 9430: 9257: 9166: 9093:

Units of measurement: history, fundamentals and redefining the SI base units (2nd ed)

8961: 8813: 8699: 8687: 8338: 8326: 8279: 8220: 8012: 7955: 7928: 7809: 7797: 7769: 7754: 7742: 7656: 7644: 7595: 7518: 7487: 7196: 7135: 7123: 6966: 6794: 6784: 6734: 6686: 6676: 6654: 6574: 6487: 6475: 6452:. The new International System of Units / Le nouveau Système international d’unités. 6331: 6240: 6215: 6142: 6130: 6020: 5884: 5807: 5795: 5759: 5682: 5639: 5614: 5426: 5416: 5328: 5155: 5101: 5056: 5019: 5009: 4976: 4850: 4806: 4796: 4604: 4594: 4547: 4537: 4441: 4431: 4408: 4398: 4238:"Digital modeling of world's first known length reference unit: The Nippur cubit rod" 3456: 3112:

region. The frequency of the light from the methane-stabilised laser was found to be

2965: 2630:

In recognition of France's role in designing the metric system, the BIPM is based in

2594: 2482: 2478: 2349: 2320: 2122: 2003: 1927: 1667: 1649:

has ancient roots which were revived in the 19th century by the modernist impetus of

1586: 1524: 1354: 1338: 1330: 1298: 1287: 1025:

Earth's circumference § Historical use in the definition of units of measurement

933: 900: 562: 430: 353: 253: 89: 9755: 9438: 4754: 4138: 3261: 1189: 1181: 1112: 433:

and proposed this unit of measurement to be called the astronomical radius (French:

9792: 9735: 9665: 9632: 9620: 9583: 9546: 9534: 9517: 9497: 9458: 9426: 9205: 9178: 9156: 9012: 8927: 8831: 8803: 8679: 8451: 8318: 8212: 8128: 7789: 7732: 7683: 7636: 7587: 7477: 7251: 7115: 6958: 6644: 6636: 6601: 6465: 6319: 6122: 6084: 5787: 5749: 5672: 5635:

Full meridian of glory: perilous adventures in the competition to measure the Earth

5604: 5539: 5320: 5098:

From artefacts to atoms: the BIPM and the search for ultimate measurement standards

5046: 4249: 4201: 3763: 3029: 2610: 2562: 2512: 2494: 2142: 2138: 1935: 1852: 1822: 1727: 1486:

Metre § Early adoption of the metre as a scientific unit of length: the forerunners

1420: 1394: 1146: 1127: 1104: 1020: 959: 947: 880: 862: 818: 771: 631:, the study of variations in gravitational acceleration was a way to determine the 566: 426: 388: 179: 156: 101: 7894: 7544: 7466:"History of the International Polar Motion Service/International Latitude Service" 7403: 7240:"La méridienne de Dunkerque à Barcelone et la déterminiation du mètre (1972-1799)" 7063:"Nomination of the STRUVE GEODETIC ARC for inscription on the WORLD HERITAGE LIST" 7033: 6878: 6346: 6077:"La méridienne de Dunkerque à Barcelone et la déterminiation du mètre (1972-1799)" 5987: 5928: 5182: 4623: 2157:

in 1830. During the mid nineteenth century, following the defeat and expulsion of

1192:, were imprisoned several times during their surveys, and Méchain died in 1804 of 485:]), which had been recently renewed. He proposed a universal toise (French: 277:. Archaeologists consider that this 51.85 cm long unit was the origin of the 93: 9820:

Resolution 1, 17th Meeting of the General Conference on Weights and Measures

8117:"Exposé historique des travaux de la commission géodésique suisse de 1862 à 1892" 7863: 7672:"Exposé historique des travaux de la commission géodésique suisse de 1862 à 1892" 7434: 7346: 7329: 7277: 7002: 6534: 6502: 6373: 6261: 6185: 6014: 5220: 4512: 4253: 3929: 2791: 2678: 2292: 2186: 2126: 1895: 1754: 1746: 1722: 1621: 1613: 1302: 1220: 1212: 858: 795: 650: 640: 628: 183: 143:, a platinum bar held in Paris. During the mid nineteenth century, following the 9587: 6847: 4430:. Dupont-Bloch, Nicolas. ( ed.). Louvain-la-Neuve: De Boeck. pp. 5–6. 4295:

Des chiffres ou des lettres : compter, calculer, mesurer à l'époque romaine

2549:

as the distance between two lines on a standard bar composed of an alloy of 90%

1276:

in his 1744 survey of France. Méchain's baseline, of a similar length (6,006.25

661:

measured at different latitudes and the flattening of the Earth considered as a

529:

when Mars was at its closest to Earth in 1672. They arrived at a figure for the

9924: 9775: 9718: 9480: 8472: 8089: 7150: 6470: 6445: 5609: 5584: 5507: 5445: 5252: 5051: 4269:"Measurement and 3D modelling of an ancient measuring device: Nippur Cubit Rod" 3105: 2985: 2874:

measurements carried out using the international prototype metre were those of

2871: 2670: 2618: 2375: 2245: 2218: 2170: 2134: 2083: 2019: 1943: 1891: 1864: 1739: 1636: 1617: 1609: 1590: 1150: 1142: 922: 834: 530: 422: 357: 195: 109: 41: 9277: 8931: 8715:

Procès-verbaux: Commission Internationale du Mètre. Réunions générales de 1872

8683: 7793: 7482: 7465: 5023: 4877:"INRP – CLEA – Archives : Fascicule N° 137, Printemps 2012 Les distances" 2747: 1839: 1290:). Although Méchain's sector was half the length of Delambre, it included the 1223:

which was surveyed by Delambre and the southern section of 333.0 km from

829:

mathematician soon independently discovered a mathematical formula to correct

9918: 9895: 9845: 9339: 9170: 8884: 8817: 8691: 8504:

The creation of the International Bureau of Weights and Measures and its work

8330: 8283: 8224: 8216: 7801: 7746: 7648: 7522: 7491: 7127: 6970: 6962: 6798: 6578: 6532: 6479: 6237:

The Measure of all Things – The Seven-Year-Odyssey that Transformed the World

6212:

The Measure of all Things – The Seven-Year-Odyssey that Transformed the World

6134: 5888: 5799: 5763: 5686: 5618: 5351: 5332: 5324: 5159: 5060: 4980: 4952:. Vol. 08 (11th ed.). Cambridge University Press. pp. 801–813. 4937: 4810: 4608: 4551: 4445: 4412: 4003: 3951: 3937: 3907: 3893: 3866: 3852: 3203: 3082: 2903: 2883: 2819: 2728: 2598: 2586: 2506: 2486: 2241: 2210: 2130: 2079: 1520: 1497: 1092: 810: 775: 526: 321: 309: 8947: 8016: 6690: 5430: 2790:

In 1921, the Nobel Prize in Physics was awarded to another Swiss scientist,

2201:(1870-1871). Napoleonic Wars fostered German nationalism which later led to 2057: 1627: 9804: 9747: 9343: 8808: 8783: 8520: 8456: 8439: 7737: 7712: 7276:

Historische Commission bei der königl. Akademie der Wissenschaften (1908),

6658: 6606: 6323: 6160:. School of Mathematics and Statistics, University of St. Andrews, Scotland 6126: 5791: 5754: 5737: 5677: 5660: 5544: 5074: 5003: 4941: 3525:

The length of the pendulum is a function of the time lapse of half a cycle

3405: 3070: 3033: 2950: 2906:

as a secondary unit of length for spectroscopic measurements, first by the

2887: 2803: 2674: 2445:) to establish a "European international bureau for weights and measures". 2287: 2007: 1860: 1712: 1708: 1700: 1679: 1322: 1193: 1177: 1155: 1046: 606: 590: 548: 534: 290: 9478:

Baird, K. M.; Howlett, L. E. (1963). "The International Length Standard".

9401: 9253:

Measure of the Earth: The Enlightenment Expedition That Reshaped Our World

8748: 8728: 7239: 7119: 6778: 6076: 5849:

The Statutes of the United Kingdom of Great Britain and Ireland [1827-

4534:

La science au péril de sa vie : les aventuriers de la mesure du monde

2862: 2759:

work led to the discovery of special alloys of iron–nickel, in particular

2601:

played a pivotal role in the unification of the metric system through the

2458: 1666:

work inaugurated under Muhammad Ali. This Commission suggested to Viceroy

726:. The Weights and Measures Commission would adopt in 1799 a flattening of 9373:

Transactions of the International Union for Cooperation in Solar Research

8023: 8006: 7768:

Drewes, Hermann; Kuglitsch, Franz; Adám, József; Rózsa, Szabolcs (2016).

7591: 7255: 6640: 6629:

Journal of Research of the National Institute of Standards and Technology

6088: 4902: 4827:[First determination of the distance from the Earth to the Sun]. 4565: 4390: 3733: 2811: 2263:

In 1867, the General Conference of the European Arc Measurement (German:

2214: 2182: 2087: 1955: 1939: 1919: 1640: 1601: 1374: 943: 814: 570: 538: 514: 504: 482: 458: 452: 414: 313: 301: 9910:. Vol. 18 (11th ed.). Cambridge University Press. p. 299. 9796: 9739: 9501: 8132: 7687: 7530: 7506: 7085: 5167: 4988: 4964: 4879:[NPRI – CLEA – Archives: Issue N ° 137, Spring 2012 Distances]. 3973: 3036:

to both the old prototype metre and the old definition of the angstrom.

1818: 1670:

the idea of buying geodetic devices which were ordered in France. While

1492: 646:

Théorie de la figure de la terre, tirée des principes de l'hydrostatique

9818: 9691: 7640: 7368:, 2004, Estudios sociales de la ciencia y la tecnologia, 23, pp. 11–30. 3349: 2989: 2895: 2780: 2398: 2015: 1778: 1631:

Ibáñez apparatus calibrated on the metric Spanish Standard and used at

1551: 1207: 1038: 687: 636: 616: 368: 348: 191: 113: 45: 32: 9669: 9624: 9016: 8322: 8116: 7671: 4205: 2914:(1927). Michelson's work in "measuring" the prototype metre to within 891:

In the 18th century, geodetic surveys found practical applications in

802:

according to gravity measurements performed under the auspices of the

9538: 9161: 9136: 8500:

La Création du Bureau International des Poids et Mesures et son Œuvre

7616: 5365:. Madrid: Imprenta de la Viuda e Hijo de D.E. Aguado. pp. 70–78. 3977: 3109: 2772: 2590: 2394: 2229: 2189:

of units of measurement respectively followed the successive fall of

2075: 2011: 1848: 1567: 1409: 1283: 1064: 1050: 955: 383:

and that this period depended on the length of the pendulum. In 1645

282: 270: 9899: 9193: 8751:

PROCÈS-VERBAUX DES SÉANCES. DEUXIÈME SÉRIE. TOME II. SESSION DE 1903

8299:"Charles Sanders Peirce and the first absolute measurement standard" 8298: 7348:

Memoires de la Société de physique et d'histoire naturelle de Genève

7331:

Memoires de la Société de physique et d'histoire naturelle de Genève

6554: 6178: 5903:"L'histoire des unités | Réseau National de la Métrologie Française" 5185:[The Royal Academy of Sciences and the Shape of the Earth]. 3472:

metres or about 150 million kilometres (93 million miles).

2631: 2528: 1847:

It was well known that by measuring the latitude of two stations in

1033: 9353:

Comptes rendus hebdomadaires des séances de l'Académie des sciences

9039:. U.S. Dept. of Commerce, National Bureau of Standards. p. 67. 7844: 6983: 5382:

Comptes rendus hebdomadaires des séances de l'Académie des sciences

3074: 3057: 2771:

in 1920. Guillaume's Nobel Prize marked the end of an era in which

2662: 2585:

and director of the German Weights and Measures Service, the Swiss

2550: 2174: 2158: 2029: 1987: 1876: 1794: 1782: 1726:

West Europe–Africa Meridian-arc: a meridian arc extending from the

1663: 1543: 1291: 1268:

being about 1.949 m). Thereafter he used, where possible, the

1117: 766:

would have been found, if they had been combined with those of the

662: 594: 392: 380: 245: 152: 4044:

for the maximum-intensity definition, with a relative uncertainty

2002:. Baeyer also planned to determine the curvature of the seas, the 1970:

coordinate geodetic surveys in the space between the parallels of

1071:

The question of measurement reform was placed in the hands of the

409:

and to the determination of the distance from Earth to the Sun by

9768: 8156:, Madrid, Imprenta de la Viuda e Hijo de D.E. Aguado, 1881, p. 78 6783:. Oxford. pp. 20, 37–38, 91–92, 70–72, 114–117, 144–147, 8. 5398: 5350:

This article incorporates text from this source, which is in the

4920: 4773: 4575: 3348:

1,650,763.73 wavelengths of light from a specified transition in

3089: 3044: 2961: 2957: 2945: 2891: 2866:

A Krypton-86 lamp used to define the metre between 1960 and 1983.

2815: 2784: 2776: 2732: 2666: 2554: 2402: 2341: 2233: 1979: 1971: 1903: 1899: 1887: 1774: 1716: 1632: 1513: 1282:), and also on a straight section of road between Vernet (in the 658: 578: 574: 522: 508: 372: 49: 9348:"Nouvelle détermination du Mètre en longueurs d'ondes lumieuses" 9321:

Travaux et Mémoires du Bureau International des Poids et Mesures

7195:(in French). De Gruyter, Incorporated. pp. 23–25, 100–109. 6539:. Vol. new ser.:v.2 (1825). Philadelphia pp. 234–278. 6182:

The metric versus the English system of weights and measures ...

6019:(in French). Springer Science & Business Media. p. 46. 4517:. University of Ottawa. Paris : Gauthier-Villars. pp. 3623:{\displaystyle \ell =g\left({\frac {T_{1/2}}{\pi }}\right)^{2}.} 2018:

in the north. In his mind, the cooperation of all the States of

1998:, in order to determine the influence of this mountain range on 1761:

measurement, it was resolved in the 1860s, at the initiative of

237:

has since 1959 officially been defined as exactly 0.9144 metre.

8241:

The Statutes of the United Kingdom of Great Britain and Ireland

8035: 7925:

Mesurer le monde: l'incroyable histoire de l'invention du mètre

5146:

Perrier, Général (1935). "Historique Sommaire de la Geodesie".

4707: 4672:

Centuries of Inventions: Encyclopedia and History of Inventions

4487: 3421:

Seconds pendulum § Relationship to the figure of the Earth

3148: 3139:

approved a conventional value of the speed of light as exactly

2345: 2067: 2053: 2049: 1991: 1947: 1856: 1806: 1786: 1654: 1539: 826: 825:

and Isaac-Charles Élisée Cellérier (8.01.1818 – 2.10.1889), a

577:

grew in importance as a means of empirically demonstrating the

491:) which was twice the length of the seconds pendulum. In 1675, 396: 266: 9515:

Maiman, T. H. (1960). "Stimulated optical radiation in ruby".

9071: 7545:"Polar motion | Earth's axis, wobble, precession | Britannica" 7402:

Jouffroy, Achille de (1785-1859) Auteur du texte (1852–1853).

5039:"Émilie Du Châtelet, un passeur scientifique au XVIIIe siècle" 2928: μm) was one of the reasons for which he was awarded the 2448: 1793:

is a ball, which on the whole can be assimilated to an oblate

9562: 7922: 7574:

Torge, Wolfgang (2016). Rizos, Chris; Willis, Pascal (eds.).

6675:. Encyclopedia Universalis. 1996. pp. 320, 370. Vol 10. 5415:. Encyclopedia Universalis. 1996. pp. 320, 370. Vol 10. 4825:"Première détermination de la distance de la Terre au Soleil" 4795:] (in French). Louvain-la-Neuve: De Boeck. pp. 5–6. 3801: 3773: 3078: 2980:

and lower operating temperatures for the lamp (which reduces

2841: 2760: 2356:, had made three direct copies of the Toise of Peru, one for 2335:

in the United States and served as standard of length in the

2316: 2071: 2063: 2025: 1966: 1790: 1704: 1658: 1243: 1224: 1199: 476: 444: 438: 334: 326: 293:

and 16 of these fingers gave a Roman foot of 29.633 cm.

286: 261: 100:. As a base unit of length, many scientists had favoured the 57: 37: 9714: 8011:(in French). Paris: Gauthier-Villars. pp. 7–8, 20, 32. 7893:

texte, Ismāʿīl-Afandī Muṣṭafá (1825-1901) Auteur du (1864).

7862:

texte, Ismāʿīl-Afandī Muṣṭafá (1825-1901) Auteur du (1886).

7433:

Delambre, Jean-Baptiste (1749–1822) Auteur du texte (1912).

7032:

texte, Ismāʿīl-Afandī Muṣṭafá (1825-1901) Auteur du (1864).

7001:

texte, Ismāʿīl-Afandī Muṣṭafá (1825–1901) Auteur du (1886).

6260:

Delambre, Jean-Baptiste (1749-1822) Auteur du texte (1912).

2384:

In the second half of the 19th century, the creation of the

2368:

also realized a copy of the Toise of Peru which was kept at

2228:

The intimate relationships that necessarily existed between

1211:

The north and south sections of the meridinal survey met at

9410:

Journal of Physics B: Atomic, Molecular and Optical Physics

8121:

Bulletin de la Société des Sciences Naturelles de Neuchâtel

7676:

Bulletin de la Société des Sciences Naturelles de Neuchâtel

7175:

J. M. López de Azcona, "Ibáñez e Ibáñez de Ibero, Carlos",

6665: 4144: 3846:

Distances measured using Google Earth. The coordinates are:

3313: 3136: 3000: 2911: 2833: 2829: 2473:

sent to the French Academy of Sciences a report drafted by

2425: 2364:

in 1821 and a third for Friedrich Bessel in 1823. In 1831,

1995: 1983: 1555: 968: 963: 918: 470: 342: 317: 305: 234: 9076:[History of the meter] (in French). Archived from 8000: 7998: 7220:"El General Ibáñez e Ibáñez de Ibero, Marqués de Mulhacén" 6353:(in French). pp. 262, 285, 288–290, 269, 276–277, 283 6109:

Martin, Jean-Pierre; McConnell, Anita (20 December 2008).

5659:

Martin, Jean-Pierre; McConnell, Anita (20 December 2008).

4006:

such that the wavelength (in air) of the cadmium line was

3032:

of air). In this way, the new definition of the metre was

3023:

The measurement of the wavelength of the krypton line was

2976:

Krypton is a gas at room temperature, allowing for easier

612: 8764: 8613:

The BIPM and the evolution of the definition of the metre

8579: 8444:

Philosophical Transactions of the Royal Society of London

7948:

commission, Internationale Erdmessung Permanente (1892).

7334:. Vol. 15. Geneve: Georg pp. 441–444, 484–485. 7189:

commission, Internationale Erdmessung Permanente (1892).

6312:

Philosophical Transactions of the Royal Society of London

5780:

Philosophical Transactions of the Royal Society of London

5742:

Philosophical Transactions of the Royal Society of London

5183:"L'Académie Royale des Sciences et la Figure de la Terre" 4425: 2104:

and Raoul Gautier (1854–1931), respectively directors of

9399: 8995:

Phelps, F. M. III (1966). "Airy Points of a Meter Bar".

8253: 8251: 7954:(in French). De Gruyter, Incorporated. pp. 99–107. 7767: 7464:

Yokoyama, Koichi; Manabe, Seiji; Sakai, Satoshi (2000).

7233: 7231: 7229: 5355: 5100:. New York Oxford: Oxford University Press. p. 13. 4325:, vol. 11, Paris: Pierre Larousse, pp. 163–164 1585:

whose president, the Swiss meteorologist and physicist,

942:

This option, with one-third of this length defining the

833:

of this device which had been noticed by Plantamour and

9864:

Encyclopaedia of Scientific Units, Weights and Measures

9060:

end on this side to show the precise length of a meter.

8438:

Ross, Clarke Alexander; James, Henry (1 January 1873).

7995: 7360: 7358: 6849:

Histoire abrégée de l'astronomie / par Ernest Lebon,...

6306:

Clarke, Alexander Ross; James, Henry (1 January 1867).

5736:

Clarke, Alexander Ross; James, Henry (1 January 1873).

4593:(in French). Louvain-la-Neuve: De Boeck. pp. 5–6. 4177:"Foundations of the international system of units (SI)" 1620:

were taken into account by Bessel when he proposed his

1234:

Delambre used a baseline of about 10 km (6,075.90

993:

It has been suggested that portions of this section be

8531:. Vol. 8 (11th ed.). 1911. pp. 801–813. 7927:. Libres Champs. Paris: Flammarion. pp. 499–520. 6439: 6437: 5174: 5085:. Vol. 8 (11th ed.). 1911. pp. 801–813. 2988:), and so it was decided to select the orange line of 1859:

measurements contained significant systematic errors.

9645: 9051:"National Bureau of Standards Replica Meter Standard" 8350: 8348: 8248: 8047:. U.S. Government Printing Office. 1966. p. 529. 7226: 6155: 5405: 4297:(in French). Musée romain de Vallon. pp. 43, 32. 4098: 3687: 3638: 3567: 3531: 3487: 3370:

Length of the path travelled by light in a vacuum in

2996: ≈ 606 nm) as the new wavelength standard. 2908:

International Union for Cooperation in Solar Research

1875:

that gave an inaccurate determination of Barcelona's

1204:. This value was set by legislation on 7 April 1795. 857:

for the flattening of the Earth when he proposed his

425:. In 1671, Jean Picard also measured the length of a 92:(1789) came a desire to replace many features of the 9023: 8718:(in French). Imprim. Nation. 1872. pp. 153–155. 8515: 8513: 7706: 7704: 7569: 7567: 7565: 7355: 7079: 7077: 7075: 6841: 6839: 6590: 6588: 6548: 6546: 6500: 6301: 6299: 6297: 6295: 5218: 4644:"Science. 1791, l'adoption révolutionnaire du mètre" 4622:

Poynting, John Henry; Thompson, Joseph John (1907).

3214: 2715:

and declared Prototype of the metre by the 1st

2699:(1.6 μm short of the international prototype). 605:

and this new data called into question the value of

9043: 8749:COMlTÉ INTERNATIONAL DES POIDS ET MESURES. (1903). 8729:COMITÉ INTERNATIONAL DES POIDS ET MESURES. (1876). 8540: 8538: 8081: 7498: 7463: 6907: 6905: 6772: 6770: 6768: 6753: 6434: 6382: 2902: ≈ 644 nm), led to the definition of the 1527:to assess temperature effects on the measurements. 507:had measured the 0.3% difference in length between 9861: 8549: 8345: 7923:Alder, Ken; Devillers-Argouarc'h, Martine (2015). 7821: 7819: 7214: 7212: 6846:Lebon, Ernest (1846–1922) Auteur du texte (1899). 6618: 6616: 6555:"Swiss Geodesy and the United States Coast Survey" 6536:Transactions of the American Philosophical Society 6444:Débarbat, Suzanne; Quinn, Terry (1 January 2019). 6111:"Joining the observatories of Paris and Greenwich" 5661:"Joining the observatories of Paris and Greenwich" 5583:Débarbat, Suzanne; Quinn, Terry (1 January 2019). 4292: 3714: 3673: 3622: 3552: 3518:{\displaystyle T=2\pi {\sqrt {\frac {\ell }{g}}}.} 3517: 3312:Platinum-iridium bar at melting point of ice (1st 2161:'s forces which brought an end to the short-lived 9454:Nobel Prize in Physics 1907 – Presentation Speech 8510: 8431: 7701: 7586:. Cham: Springer International Publishing: 3–18. 7582:. International Association of Geodesy Symposia. 7562: 7149:von Struve, Friedrich Georg Wilhelm (July 1857). 7072: 6836: 6585: 6543: 6292: 5251:von Struve, Friedrich Georg Wilhelm (July 1857). 4628:(4th ed.). London: Charles Griffin. p. 4335: 2097:Association Géodesique réduite entre États neutre 1765:who would become the first president of both the 1169:of a quarter-circle), with 100 minutes to a 710:meanwhile found at the same time a flattening of 9916: 9853: 9834: 9832: 9830: 9337: 9030:Page, Chester H.; Vigoureux, Paul, eds. (1975). 8535: 7351:. Vol. 16. Geneve: Georg pp. 165–196. 6902: 6826:Hassler, Harriet; Burroughs, Charles A. (2007). 6825: 6765: 6156:O'Connor, J. J.; Robertson, E. F. (April 2003). 5994:(in French). pp. 288–290, 269, 276–277, 283 5008:. Normandie roto impr.). Paris: Robert Laffont. 4786: 4621: 4588: 4266: 2575:International Committee for Weights and Measures 2571:International Committee for Weights and Measures 2116: 1595:International Committee for Weights and Measures 1512:. Trained in geodesy in Switzerland, France and 1215:, seen here dominating the Rodez skyline at left 911:. The unit of length used by the French was the 521:measured the parallax of Mars between Paris and 9315: 9302:Stephen Hawking, Paris, Dunod, 2003, 2014, 929 9278:"Lettres philosophiques/Lettre 15 - Wikisource" 8847:Guillaume, Charles-Édouard (11 December 1920). 7816: 7209: 6613: 6338: 6108: 6068: 5770: 5658: 5638:. New York; London: Copernicus Books/Springer. 4932: 4930: 4761:troisième volume de la Base du Système métrique 3069:The krypton-86 discharge lamp operating at the 2944:that this was due to the presence of different 2741:Metre § Metrology and paradigm shift in physics 1771:International Committee for Weights and Measure 8881:National Institute of Standards and Technology 8464: 7983:. International Bureau of Weights and Measures 7980:The International Metre Commission (1870–1872) 6365: 4531: 3003:in 1960 agreed a new definition of the metre: 2613:and to promote the foundation of a permanent 1067:, Spain – the southern end of the meridian arc 928:Despite scientific progresses in the field of 312:. A Roman cubit was equivalent to 1.5 feet, a 9827: 9029: 8408: 8406: 7848:Bulletin de la Société de géographie d'Égypte 7401: 6987:Bulletin de la Société de géographie d'Égypte 6937:Bessel, Friedrich Wilhelm (1 December 1841). 6877:Puissant, Louis (1769–1843) Auteur du texte. 6443: 6391:"Fixation de la longueur définitive du mètre" 6371: 6179:National Industrial Conference Board (1921). 5961:"Fixation de la longueur définitive du mètre" 5952: 5582: 4956: 921:, which became the geodetic unit used in the 537:, which had been measured by their colleague 497: 9702:International Bureau of Weights and Measures 9477: 9395: 9393: 9225:"Einstein, le révolutionnaire de la lumière" 8949:International Bureau of Weights and Measures 8630: 8618:International Bureau of Weights and Measures 8606: 8604: 8602: 8600: 8598: 8506:]. Paris: Gauthier-Villars. p. 321. 8167:"Metric Act of 1866 – US Metric Association" 7845:Jamʻīyah al-Jughrāfīyah al-Miṣrīyah (1876). 7179:, vol. VII, 1–2, Scribner's, New York, 1981. 6984:Jamʻīyah al-Jughrāfīyah al-Miṣrīyah (1876). 6912:Viik, T (2006). "F. W. Bessel and geodesy". 6102: 5437: 4927: 4506: 4504: 4502: 4458:: CS1 maint: multiple names: authors list ( 4293:Agustoni, Clara; Buchillier, Carmen (2018). 3832: 3825: 3817: 3809: 3799: 3791: 3781: 3771: 3761: 3752: 3746: 3283: 2717: 2709: 2683: 2649: 2636: 2615:International Bureau of Weights and Measures 2567:International Bureau of Weights and Measures 2537: 2521: 2464:International Bureau of Weights and Measures 2264: 2258: 2095: 1890:recommending international collaboration in 1745:Seventeen years after Bessel calculated his 1401: 1277: 1263: 1257: 1249: 1241: 1235: 1197: 954:shortly after gaining independence from the 912: 841:to determine a remarkably accurate value of 750:had been excluded, whereas a value close to 644: 542: 486: 474: 462: 450: 442: 387:was the first to determine the length of a " 167: 136: 9773:-stabilized He–Ne 473-THz (633-nm) laser". 9065: 8988: 8903: 8901: 7908:: CS1 maint: numeric names: authors list ( 7878:: CS1 maint: numeric names: authors list ( 7470:International Astronomical Union Colloquium 7449:: CS1 maint: numeric names: authors list ( 7418:: CS1 maint: numeric names: authors list ( 7047:: CS1 maint: numeric names: authors list ( 7017:: CS1 maint: numeric names: authors list ( 6894:: CS1 maint: numeric names: authors list ( 6862:: CS1 maint: numeric names: authors list ( 6518:: CS1 maint: numeric names: authors list ( 6305: 6275:: CS1 maint: numeric names: authors list ( 6205: 6203: 5944:: CS1 maint: numeric names: authors list ( 5735: 5556: 5554: 5526: 5464: 5236:: CS1 maint: numeric names: authors list ( 5067: 4787:Bond, Peter; Dupont-Bloch, Nicolas (2014). 4625:A Textbook of Physics: Properties of Matter 4589:Bond, Peter; Dupont-Bloch, Nicolas (2014). 4322:Grand dictionnaire universel du XIXe siècle 4133: 4131: 4076:"BIPM - Commission internationale du mètre" 4040:for the "centre-of-gravity" definition and 2565:was signed on 20 May 1875 in Paris and the 1608:of the Survey of the Coast, shortly before 1231:, Barcelona which was surveyed by Méchain. 551:used this measurement for establishing his 320:contained 1000 paces or 5000 feet. A Roman 77: 9859: 9698:General Conference on Weights and Measures 9600: 9198:Journal de Physique Théorique et Appliquée 9084: 8565:Institut de France – Académie des sciences 8403: 8191:Bessel, Friedrich Wilhelm (1 April 1840). 7947: 7851:. University of Michigan. . pp. 6–16. 7301: 7188: 7148: 6990:. University of Michigan. . pp. 6–16. 6811:: CS1 maint: location missing publisher ( 5979: 5480:Institut de France – Académie des sciences 5306: 5250: 4745: 4743: 4462:) CS1 maint: numeric names: authors list ( 4319:Larousse, Pierre, ed. (1874), "Métrique", 4308: 4306: 4304: 4235: 3439:The modern value of the solar parallax is 3039: 2857: 2644:(CGPM) rather than the French government. 2624:Conservatoire national des Arts et Métiers 2533:General Conference on Weights and Measures 1508:was appointed first Superintendent of the 1329:: Gabriel Císcar and Agustín de Pedrayes, 1240:) in length along a straight road between 1029:Meridian arc § History of measurement 9402:"Optical frequency/wavelength references" 9390: 9270: 9191: 9160: 8943: 8941: 8846: 8807: 8595: 8497: 8455: 8437: 8364:Bureau International des Poids et Mesures 8290: 8257: 8159: 8029: 7973: 7971: 7736: 7614: 7481: 7426: 7142: 7109: 6930: 6921: 6648: 6605: 6469: 6344: 5985: 5926: 5862: 5753: 5676: 5608: 5543: 5356:Ibáñez e Ibáñez de Ibero, Carlos (1881). 5291: 5181:Levallois, Jean-Jacques (May–June 1986). 5180: 5050: 4749: 4510: 4499: 4493: 2711:Bureau International des Poids et Mesures 2569:was created under the supervision of the 2523:Bureau International des Poids et Mesures 2331:in 1799. One of them became known as the 2315:, and unique artifacts made of different 2281:Metre § International prototype metre bar 1583:International Meteorological Organisation 1345:: Prospero Balbo, Antonio Vassali Eandi, 657:which established a relationship between 9894: 9249: 9194:"La mesure rapide des bases géodésiques" 8898: 8753:. Paris: GAUTHIER-VILLARS. pp. 5–7. 7432: 6832:. NIST Research Library. pp. 51–52. 6259: 6200: 6012: 5551: 5496:, Neuchâtel, imprimerie Attinger frères. 5001: 4936: 4318: 4170: 4168: 4166: 4164: 4162: 4160: 4158: 4156: 4154: 4128: 3043: 2861: 2746: 2719:Conférence Générale des Poids et Mesures 2639:Conférence générale des poids et mesures 2539:Conférence Générale des Poids et Mesures 2447: 2374: 2303:had brought to the United States in 1805 2286: 1838: 1773:, to remeasure the arc of meridian from 1721: 1626: 1542:to the basic units of the metre and the 1491: 1408: 1294:and hitherto unsurveyed parts of Spain. 1206: 1122: 1075:, who appointed a commission chaired by 1055: 1032: 975: 952:redefining the yard in the United States 909:Principal Triangulation of Great Britain 879: 611: 347: 244: 198:; this definition was reworded in 2019: 31: 27:Origins and values of the unit of length 9558: 9556: 8960:(8th ed.), pp. 142–143, 148, 8907: 8732:PROCÈS-VERBAUX DES SÉANCES DE 1875-1876 8470: 8386:"BIPM – International Metre Commission" 8237: 8114: 8087: 7669: 7504: 7237: 6074: 5845: 5443: 5307:Rath, Geheimen; Ritter (January 1842). 5145: 5036: 4962: 4740: 4701: 4668: 4301: 4236:Duran, Zaide; Aydar, Umut (July 2012). 3715:{\displaystyle g={\ell \cdot \pi ^{2}}} 3674:{\displaystyle T_{1/2}=1\ \mathrm {s} } 3285: 2557:, measured at the melting point of ice. 2509:according to the progress of sciences. 2155:Office of Standard Weights and Measures 585:promoted in France in combination with 14: 9917: 9838: 9514: 9192:Guillaume, C.-H.-Ed (1 January 1906). 8994: 8954:The International System of Units (SI) 8938: 8842: 8840: 8744: 8742: 8555: 8354: 8296: 8260:"Le Systeme Metrique est-il en Peril?" 8190: 7968: 7379:"c à Paris; vitesse de la lumière ..." 7282:Allgemeine Deutsche Biographie, Bd. 54 6936: 6600:, vol. 163, London, p. 463, 6594: 6552: 6115:Notes and Records of the Royal Society 6042:"How France created the metric system" 5865:"Le Systeme Metrique est-il en Peril?" 5776: 5729: 5699: 5665:Notes and Records of the Royal Society 5631: 5625: 5538:, vol. 163, London, p. 463, 5532: 5470: 4901: 4829:Les 350 ans de l'Observatoire de Paris 4574:(in French). pp. 3–4 – via 4564: 4476: 4174: 3739: 3169:This definition was reworded in 2019: 3065:Metre § Speed of light definition 2414:French Geodesic Mission to the Equator 1477:French Geodesic Mission to the Equator 768:French Geodetic Mission to the Equator 72:that is considered to have begun with 9090: 8781: 8735:. Paris: Gauthier-Villars. p. 3. 8661: 8577: 8297:Crease, Robert P. (1 December 2009). 7892: 7861: 7710: 7615:Levallois, J. J. (1 September 1980). 7573: 7439:pp. 202–203, 2015, 141–142, 178. 7083: 7031: 7000: 6845: 6829:Ferdinand Rudolph Hassler (1770–1843) 6776: 6234: 6209: 5578: 5576: 5095: 4389: 4385: 4383: 4151: 2169:an autonomous tributary state of the 1400: 997:out into another article titled 407:Newton's law of universal gravitation 182:bars kept across the globe. A better 9553: 9072:Direction générale des Entreprises. 8876:National Prototype Meter No. 27 8004: 7507:"Historique Sommaire De La Geodesie" 6911: 6876: 6622: 6239:. London: Abacus. pp. 240–241. 6214:. London: Abacus. pp. 227–230. 6172: 6013:Capderou, Michel (31 October 2011). 5895: 5505: 5277: 4965:"Historique Sommaire De La Geodesie" 4536:. Paris: Vuibert. pp. 124–125. 3220:Definitions of the metre since 1798 2651:A tous les temps, à tous les peuples 2471:Saint Petersburg Academy of Sciences 2271:) called for the creation of a new, 2238:International Association of Geodesy 2129:led to the adoption of the metre in 1952:United Kingdoms of Sweden and Norway 1699:with an arc running northwards from 1000:Meridian arc of Delambre and Méchain 979: 240: 9250:Ferreiro, Larrie D. (31 May 2011). 8837: 8739: 8498:Guillaume, Charles-Édouard (1927). 6388: 5958: 5122:"Clairaut's equation | mathematics" 4793:The exploration of the solar system 4397:. Paris: Éd. du Seuil. p. 38. 4175:Nelson, Robert A. (December 1981). 2971: 2890:(1906), both using the red line of 2727:These support locations are at the 85:system to ease their calculations. 80:De revolutionibus orbium coelestium 24: 8849:"Nobel lecture: Invar and Elinvar" 8638:"A Note on the History of the IAG" 8414:"A Note on the History of the IAG" 7177:Dictionary of Scientific Biography 6289:The wall plaque next to the metre. 6039: 6016:Satellites : de Kepler au GPS 5573: 5139: 4426:Bond, Peter, (1948- ...). (2014). 4380: 3667: 2853:the Sun during an eclipse in 1919. 2611:Diplomatic Conference of the Metre 2386:International Geodetic Association 2358:Friedrich Georg Wilhelm von Struve 1855:causing wear and consequently the 1767:International Geodetic Association 1707:would bring the course of a major 1361:. The French commission comprised 1173:and 100 seconds to a minute. 1021:Metre § Meridional definition 861:. This was also the result of the 804:International Geodetic Association 748:French Geodetic Mission to Lapland 635:, whose crucial parameter was the 589:mathematical work and because the 176:International Geodetic Association 25: 9941: 9888: 8908:Barrell, H. (1962). "The Metre". 8258:Guillaume, Ed. (1 January 1916). 8152:Carlos Ibáñez e Ibáñez de Ibero, 6711:. 8 December 2015. Archived from 5863:Guillaume, Ed. (1 January 1916). 5037:Touzery, Mireille (3 July 2008). 4713:"Selected Astronomical Constants" 3215:History of definitions since 1798 3007:The metre is the length equal to 2844:. According to Newton, space was 2299:produced in 1799 in Paris, which 2090:. However, the activities of the 1886:sent a memorandum to the King of 403:Kepler's laws of planetary motion 9811: 9762: 9708: 9684: 9639: 9594: 9508: 9471: 9445: 9364: 9331: 9309: 9296: 9243: 9222: 9216: 9210:10.1051/jphystap:019060050024200 9185: 9129: 9099: 8977:from the original on 4 June 2021 8867: 8824: 8775: 8757: 8722: 8706: 8655: 8571: 8491: 8378: 8231: 8184: 8146: 8115:Zuerich, ETH-Bibliothek (1892). 8108: 8088:Brunner, Jean (1 January 1857). 8051: 7941: 7916: 7886: 7855: 7838: 7761: 7670:Zuerich, ETH-Bibliothek (1892). 7663: 7608: 7537: 7457: 7395: 7371: 7366:Revista Colombiana de Sociología 7338: 7321: 7295: 7269: 7238:Zuerich, ETH-Bibliothek (1991). 7182: 7169: 7055: 7025: 6994: 6977: 6870: 6623:Parr, Albert C. (1 April 2006). 6417:"Histoire du mètre | Métrologie" 6345:Levallois, Jean-Jacques (1986). 6075:Zuerich, ETH-Bibliothek (1991). 5986:Levallois, Jean-Jacques (1986). 5852:. H.M. statute and law printers. 5444:Brunner, Jean (1 January 1857). 5345: 5043:La revue pour l'histoire du CNRS 4789:L'exploration du système solaire 4669:Lucendo, Jorge (23 April 2020). 4591:L'exploration du système solaire 4428:L'exploration du système solaire 4312: 4036:The measured speed of light was 4030: 4013: 4000:International Astronomical Union 3992: 3982: 2894:. These results, which gave the 2739:This section is an excerpt from 2279:This section is an excerpt from 2163:French occupation of Lower Egypt 2153:in 1807 and the creation of the 1960:Central European Arc Measurement 1817:, in particular the latitude of 1484:This section is an excerpt from 1426:In 1799, a commission including 1419:This section is an excerpt from 984: 917:, while the English one was the 405:served both to the discovery of 159:of 1875 at the beginning of the 98:the traditional units of measure 9839:Wilkie, Tom (27 October 1983). 9256:. Basic Books. pp. 19–23. 9107:"BIPM – la définition du mètre" 8357:"Don Carlos Ibanez (1825–1891)" 8032:, pp. 8, 158–159, 176–177. 7770:"The Geodesist's Handbook 2016" 6819: 6727: 6697: 6526: 6494: 6409: 6283: 6253: 6228: 6149: 6059: 6033: 6006: 5920: 5856: 5839: 5814: 5693: 5652: 5506:Wolf, Rudolf (1 January 1891). 5499: 5486: 5369: 5339: 5300: 5271: 5244: 5212: 5114: 5089: 5030: 4995: 4895: 4869: 4843: 4817: 4780: 4720:The Astronomical Almanac Online 4709:United States Naval Observatory 4687: 4662: 4636: 4615: 4582: 4558: 4525: 4470: 4419: 4355: 4329: 4106:"BIPM – la définition du mètre" 3840: 3725: 3475: 3449: 3433: 2673:", named after French engineer 2499:Carlos Ibáñez e Ibáñez de Ibero 2340:main references for geodesy in 2149:prompted the foundation of the 1763:Carlos Ibáñez e Ibáñez de Ibero 1685:Carlos Ibáñez e Ibáñez de Ibero 1445:Spanish-French geodetic mission 1141:Borda was an avid supporter of 886:Anglo-French Survey (1784–1790) 875:Carlos Ibáñez e Ibáñez de Ibero 437:). He found the value of 440.5 151:, the metre gained adoption in 9147:(3397): 874. 1 December 1934. 8544: 8059:"Borda et le système métrique" 6421:metrologie.entreprises.gouv.fr 6372:Larousse, Pierre (1866–1877). 4851:"1967LAstr..81..234G Page 234" 4764:(in French). pp. 523, 529 4286: 4260: 4229: 4212: 4140:9th edition of the SI Brochure 4068: 3998:The IUSR (later to become the 2319:with distinct coefficients of 2092:International Latitude Service 1600:In 1834, Hassler, measured at 511:(in French Guiana) and Paris. 275:Istanbul Archaeological Museum 13: 1: 9860:Cardarelli, François (2003). 9841:"Time to remeasure the metre" 9693:Resolution 2 of the 15th CGPM 8479:(in French). pp. 150–153 8096:(in French). pp. 150–153 7084:Soler, T. (1 February 1997). 6760:Heinrich VON WILD (1833–1902) 5514:(in French). pp. 370–371 5452:(in French). pp. 150–153 4511:Bigourdan, Guillaume (1901). 4062: 2751:Invar wire baseline apparatus 2546:International Prototype Metre 2457:preliminary proposal made in 2362:Heinrich Christian Schumacher 2273:international prototype metre 2117:International prototype metre 1574:Mitteleuropaïsche Gradmessung 1421:Metre § Meridional definition 1043:Church of Saint-Éloi, Dunkirk 907:Observatories and led to the 149:independence of Latin America 40:was one ten-millionth of the 8522:"Earth, Figure of the" 6596:length by Sir Henry James", 5534:length by Sir Henry James", 5076:"Earth, Figure of the" 5005:Les passions intellectuelles 5002:Badinter, Élisabeth (2018). 4943:"Earth, Figure of the" 4722:, p. K7, archived from 4675:. Jorge Lucendo. p. 246 4477:Dubost, Christopher (1818). 4254:10.1016/j.culher.2011.12.006 4242:Journal of Cultural Heritage 3759:, not to the later value in 3459:has been defined as exactly 3019:of the krypton 86 atom. 2850:Einstein's theory of gravity 1672:Mahmud Ahmad Hamdi al-Falaki 1581:in 1863, and by that of the 609:as Picard had calculated it. 597:through geodetic surveys in 553:law of universal gravitation 441:of the Toise of Châtelet (a 345:measured three London feet. 161:Second Industrial Revolution 7: 9870:Springer-Verlag London Ltd. 9849:(27 October 1983): 258–263. 9696:. 15th Meeting of the 9588:10.1103/PhysRevLett.29.1346 8997:American Journal of Physics 8065:(in French). Archived from 5907:metrologie-francaise.lne.fr 4367:enccre.academie-sciences.fr 4342:enccre.academie-sciences.fr 4267:Z. Duran; U. Aydar (2008). 3399: 2999:Accordingly, the 11th 2882:(1892–1893) and of Benoît, 2796:Michelson–Morley experiment 2393:. Furthermore, advances in 2165:, the metre was adopted in 2102:H.G. van de Sande Bakhuyzen 1986:and Trunz (German name for 1371:Charles-Augustin de Coulomb 36:An early definition of the 10: 9946: 9431:10.1088/0953-4075/38/9/003 7302:D'Alembert, Jean Le Rond. 6598:Philosophical Transactions 6471:10.1016/j.crhy.2018.12.002 5610:10.1016/j.crhy.2018.12.002 5536:Philosophical Transactions 5280:"F. W. Bessel and geodesy" 5052:10.4000/histoire-cnrs.7752 4650:(in French). 25 March 2021 4042:299 792.4587(11) km s 4038:299 792.4562(11) km s 3062: 3054:Kastler-Brossel Laboratory 2814:'s pendulum experiment in 2738: 2503:French Academy of Sciences 2407:gravitational acceleration 2337:United States Coast Survey 2278: 2094:were continued through an 1523:at that time and measured 1483: 1418: 1176:The task of surveying the 1045:– the northern end of the 1018: 395:with a half-period of one 385:Giovanni Battista Riccioli 377:gravitational acceleration 8932:10.1080/00107516208217499 8782:Quinn, Terry (May 2019). 8684:10.1007/s00190-004-0423-0 8197:Astronomische Nachrichten 7794:10.1007/s00190-016-0948-z 7505:Perrier, Général (1935). 7483:10.1017/S0252921100061285 6943:Astronomische Nachrichten 5313:Astronomische Nachrichten 4963:Perrier, Général (1935). 2775:was leaving the field of 2765:Charles-Edouard Guillaume 2431:Ferdinand Rudolph Hassler 2401:have led to a new era of 2301:Ferdinand Rudolph Hassler 2100:thanks to the efforts of 1525:coefficients of expansion 1506:Ferdinand Rudolph Hassler 946:, was also considered by 899:, which aimed to connect 867:Ferdinand Rudolph Hassler 690:gave him a flattening of 519:Giovanni Domenico Cassini 411:Giovanni Domenico Cassini 352:The Meridian room of the 250:Giovanni Domenico Cassini 9095:. Springer. p. 108. 8355:Hirsch, Adolphe (1891). 8217:10.1002/asna.18400171302 8044:NIST Special Publication 6963:10.1002/asna.18420190702 6673:Encyclopedia Universalis 6553:Cajori, Florian (1921). 5413:Encyclopedia Universalis 5325:10.1002/asna.18420190702 5259:(in French). p. 509 5096:Quinn, Terry J. (2012). 3732:further information see 3426: 3380:of a second (17th CGPM) 2910:(1907) and later by the 2808:Descartes' Vortex theory 2603:European Arc Measurement 2489:in all scientific work. 2439:European Arc Measurement 2311:were defined by primary 2221:. During the process of 2207:Technological Revolution 2034:European Arc Measurement 1867:and later discovered by 1738:is depicted rather than 1676:Ismail Mustafa al-Falaki 1653:who founded in Sabtieh, 1614:meridian arc measurement 1538:and proposed adding the 1357:who had been invited by 839:Friedrich Robert Helmert 813:which was first used in 800:Friedrich Robert Helmert 772:Friedrich Wilhelm Bessel 204:speed of light in vacuum 44:, the distance from the 9907:Encyclopædia Britannica 9649:Applied Physics Letters 9604:Applied Physics Letters 9567:Physical Review Letters 9055:Smithsonian Institution 8556:Pérard, Albert (1957). 8528:Encyclopædia Britannica 8238:Britain, Great (1824). 7308:artflsrv04.uchicago.edu 7278:"Schubert, Theodor von" 7068:. pp. 40, 143–144. 6450:Comptes Rendus Physique 6158:"Jean Charles de Borda" 5846:Britain, Great (1824). 5700:Portet, Pierre (2011). 5589:Comptes Rendus Physique 5471:Pérard, Albert (1957). 5126:Encyclopedia Britannica 5082:Encyclopædia Britannica 4949:Encyclopædia Britannica 4911:(in French). p. 23 4532:Simaan, Arkan. (2001). 4336:Chevalier De Jaucourt. 4225:. June 2010. p. 2. 3553:{\displaystyle T_{1/2}} 3040:Speed of light standard 2984:of the line due to the 2938:measurement uncertainty 2858:Interferometric options 2828:changed conceptions of 2607:Wilhelm Julius Foerster 2579:Wilhelm Julius Foerster 2475:Otto Wilhelm von Struve 2443:Europäische Gradmessung 2397:combined with those of 2267:Europäische Gradmessung 2046:Charles-Eugène Delaunay 1982:) and the meridians of 1906:, seven German states ( 1803:Jean Le Rond d'Alembert 1689:Frutos Saavedra Meneses 1577:) on the initiative of 1145:: he had invented the " 668:Pierre-Simon de Laplace 621:Repsold-Bessel pendulum 360:is drawn on the ground. 356:(or Cassini room): the 9930:History of measurement 9379:: 18–34. 21 May 1907. 8809:10.1002/andp.201800355 8471:Brunner, Jean (1857). 8457:10.1098/rstl.1873.0014 8063:Association Mesure Lab 7738:10.1002/andp.201800355 6607:10.1098/rstl.1873.0014 6559:The Scientific Monthly 6324:10.1098/rstl.1867.0010 6127:10.1098/rsnr.2008.0029 6083:(in French): 377–378. 5822:"The seconds pendulum" 5792:10.1098/rstl.1867.0010 5755:10.1098/rstl.1873.0014 5717:Cite journal requires 5678:10.1098/rsnr.2008.0029 5545:10.1098/rstl.1873.0014 4496:, pp. 8, 158–159. 3833: 3826: 3818: 3810: 3800: 3792: 3782: 3772: 3762: 3753: 3747: 3716: 3675: 3624: 3554: 3519: 3284: 3252:part of one half of a 3060: 3021: 2930:Nobel Prize in Physics 2867: 2769:Nobel Prize in Physics 2752: 2725: 2718: 2710: 2684: 2650: 2637: 2538: 2522: 2453: 2409:by means of pendulum. 2381: 2304: 2265: 2259: 2223:unification of Germany 2203:unification of Germany 2096: 1844: 1837: 1799:Friedrich von Schubert 1781:and to extend it from 1747:ellipsoid of reference 1743: 1643: 1560:Alexander von Humboldt 1536:Earth's magnetic field 1501: 1432:Jean Henri van Swinden 1415: 1402: 1307:Jean Henri van Swinden 1286:area) and Salces (now 1278: 1264: 1258: 1250: 1242: 1236: 1216: 1198: 1186:Jean-Baptiste Delambre 1138: 1068: 1053: 913: 888: 859:ellipsoid of reference 823:Charles Sanders Peirce 651:Alexis Claude Clairaut 645: 624: 543: 498: 487: 475: 463: 451: 443: 361: 269:, on the banks of the 265:bar was discovered in 257: 168: 137: 78: 61: 9901:"Metric System" 9137:"Dr. C. E. Guillaume" 9091:Gupta, S. V. (2020). 7711:Quinn, Terry (2019). 7120:10.1007/s001900050086 6777:Quinn, T. J. (2012). 6347:"La Vie des sciences" 5988:"La Vie des sciences" 5632:Murdin, Paul (2009). 3717: 3676: 3625: 3555: 3520: 3047: 3005: 2898:of the cadmium line ( 2865: 2750: 2705: 2451: 2378: 2366:Henri-Prudence Gambey 2290: 1932:Saxe-Coburg and Gotha 1842: 1826: 1811:Adrien-Marie Legendre 1725: 1630: 1564:Wilhelm Edouard Weber 1495: 1436:Adrien-Marie Legendre 1412: 1393:, Pierre Méchain and 1391:Louis Lefèvre-Ginneau 1387:Pierre- Simon Laplace 1383:Joseph-Louis Lagrange 1363:Jean-Charles de Borda 1210: 1132:Jean-Charles de Borda 1126: 1077:Jean-Charles de Borda 1059: 1036: 976:Meridional definition 884:Triangulation of the 883: 778:and found a value of 708:Adrien-Marie Legendre 643:. In his famous work 615: 541:in 1669 as 3,269,000 365:Scientific revolution 351: 273:, and is kept in the 248: 110:passing through Paris 70:Scientific Revolution 35: 8911:Contemporary Physics 8887:on 16 September 2008 7592:10.1007/1345_2015_42 7382:expositions.obspm.fr 7256:10.5169/seals-234595 6641:10.6028/jres.111.003 6089:10.5169/seals-234595 5702:"La mesure de Paris" 5208:– via Gallica. 3952:41.36333°N 2.16694°E 3908:44.43250°N 2.57333°E 3867:51.03556°N 2.37611°E 3751:are referred to the 3685: 3636: 3565: 3529: 3485: 3225:Basis of definition 3141:299 792 458 m s 2956:Several isotopes of 2543:), establishing the 2501:intervened with the 2391:electrical telegraph 2309:units of measurement 2195:Second French Empire 1908:Grand Duchy of Baden 1815:vertical deflections 1751:vertical deflections 1668:Mohammed Sa'id Pasha 1532:Carl Friedrich Gauss 1349:: Pietro Franchini, 1341:: Ambrogio Multedo, 1335:Johann Georg Tralles 1270:triangulation points 871:Carl Friedrich Gauss 493:Tito Livio Burattini 341:, while the English 112:, assuming an Earth 66:history of the metre 9797:10.1364/OL.8.000136 9789:1983OptL....8..136J 9740:10.1364/OL.8.000133 9732:1983OptL....8..133P 9662:1972ApPhL..20..133E 9617:1973ApPhL..22..196B 9580:1972PhRvL..29.1346E 9531:1960Natur.187..493M 9502:10.1364/AO.2.000455 9494:1963ApOpt...2..455B 9423:2005JPhB...38S.469H 9385:1908TIUCS...2...17. 9338:Benoît, Jean-René; 9153:1934Natur.134R.874. 9074:"Histoire du mètre" 9009:1966AmJPh..34..419P 8924:1962ConPh...3..415B 8800:2019AnP...53100355Q 8676:2005JGeod..78..558T 8315:2009PhT....62l..39C 8276:1916LAstr..30..242G 8209:1840AN.....17..193B 8133:10.5169/seals-88335 8005:Wolf, M. C (1882). 7786:2016JGeod..90..907D 7729:2019AnP...53100355Q 7688:10.5169/seals-88335 7633:1980BGeod..54..248L 7621:Bulletin géodésique 7617:"Notice historique" 7517:: 117–129, p. 128. 7157:. pp. 509, 510 7102:1997JGeod..71..176S 6955:1841AN.....19...97B 6715:on 18 December 2023 6571:1921SciMo..13..117C 6508:pp. 93–94, 10. 6462:2019CRPhy..20....6D 6389:Suzanne, Débarbat. 6235:Alder, Ken (2002). 6210:Alder, Ken (2002). 5959:Suzanne, Débarbat. 5881:1916LAstr..30..242G 5601:2019CRPhy..20....6D 5199:1986CRASG...3..261L 5187:La Vie des Sciences 4975:: 117–129, p. 128. 4751:Biot, Jean-Baptiste 4198:1981PhTea..19..596N 4185:The Physics Teacher 4147:, 2019, p. 131 4086:on 18 November 2018 3963:Montjuïc, Barcelona 3947: / 3903: / 3862: / 3221: 2978:isotopic enrichment 2876:Albert A. Michelson 2800:luminiferous aether 2798:had questioned the 2527:) to be located in 2517:Convention du Mètre 2354:Jean Nicolas Fortin 2325:Toise de l'Académie 2260:mètre des Archives. 2199:Franco-Prussian War 2191:First French Empire 2151:Survey of the Coast 2147:American Revolution 2052:at the Congress of 2042:Franco-Prussian War 2000:vertical deflection 1976:Freetown Christiana 1884:Johann Jacob Baeyer 1873:vertical deflection 1869:Seth Carlo Chandler 1843:Struve Geodetic Arc 1759:Struve Geodetic Arc 1711:back to land where 1697:Struve Geodetic Arc 1622:reference ellipsoid 1579:Johann Jacob Baeyer 1546:in the form of the 1510:Survey of the Coast 1496:Triangulation near 1428:Johan Georg Tralles 1343:Kingdom of Sardinia 1134:and constructed by 1101:Anglo-French Survey 1073:Academy of Sciences 897:Anglo-French Survey 837:. This would allow 796:reference ellipsoid 633:figure of the Earth 591:radius of the Earth 495:suggested the term 300:was divided into 4 145:American Revolution 74:Nicolaus Copernicus 52:, measured along a 8788:Annalen der Physik 8664:Journal of Geodesy 7774:Journal of Geodesy 7717:Annalen der Physik 7641:10.1007/BF02521470 7549:www.britannica.com 7090:Journal of Geodesy 6916:. pp. 10, 6. 5286:. pp. 10, 6. 5045:(in French) (21). 4908:Mesure de la terre 4855:adsbit.harvard.edu 4571:Mesure de la terre 3712: 3671: 3620: 3550: 3515: 3416:History of geodesy 3411:Length measurement 3286:Mètre des Archives 3219: 3114:88.376 181 627(50) 3061: 2868: 2838:general relativity 2826:special relativity 2767:, was granted the 2753: 2685:mètre des Archives 2583:Berlin Observatory 2581:, director of the 2454: 2435:Metric Act of 1866 2382: 2370:Altona Observatory 2305: 2297:Mètre des Archives 2209:a period in which 2179:continental Europe 2167:Khedivate of Egypt 2159:Napoleon Bonaparte 2110:Geneva Observatory 2106:Leiden Observatory 2056:in 1871. In 1874, 2010:in the south, the 1924:Kingdom of Prussia 1916:Kingdom of Hanover 1912:Kingdom of Bavaria 1900:Kingdom of Belgium 1882:As early as 1861, 1845: 1744: 1736:Greenwich meridian 1647:Egyptian astronomy 1644: 1502: 1416: 1403:Mètre des Archives 1319:Kingdom of Denmark 1315:Lorenzo Mascheroni 1311:Cisalpine Republic 1217: 1139: 1109:Jean-Baptiste Biot 1069: 1054: 958:. The idea of the 893:French cartography 889: 625: 583:Émilie du Châtelet 559:Christiaan Huygens 435:Rayon Astronomique 362: 258: 170:Mètre des Archives 139:Mètre des Archives 76:'s publication of 62: 9878:978-1-4471-1122-1 9670:10.1063/1.1654077 9625:10.1063/1.1654608 9574:(19): 1346–1349. 9525:(4736): 493–494. 9282:fr.wikisource.org 9263:978-0-465-02345-5 9223:Huet, Sylvestre. 9017:10.1119/1.1973011 8567:. pp. 26–28. 8323:10.1063/1.3273015 8069:on 29 August 2023 7961:978-3-11-128691-4 7934:978-2-08-130761-2 7868:. pp. 10–11. 7601:978-3-319-30895-1 7202:978-3-11-128691-4 7007:. pp. 10–11. 6852:pp. 168–171. 6790:978-0-19-990991-9 6682:978-2-85229-290-1 6661:– via NIST. 6026:978-2-287-99049-6 5934:pp. viii–ix. 5931:Biot et Arago,... 5826:www.roma1.infn.it 5482:. pp. 26–28. 5422:978-2-85229-290-1 5389:: 1463–1466. 1880 5107:978-0-19-530786-3 5015:978-2-221-20345-3 4695:Misura Universale 4395:Le mètre du monde 4206:10.1119/1.2340901 4025:3.392 231 376(12) 4021:3.392 231 404(12) 3957:41.36333; 2.16694 3913:44.43250; 2.57333 3887:– Belfry, Dunkirk 3872:51.03556; 2.37611 3665: 3605: 3510: 3509: 3457:astronomical unit 3397: 3396: 3256:, measurement by 3094:helium–neon laser 3050:helium–neon laser 2924:of a wavelength ( 2802:in 1905, just as 2595:Heinrich von Wild 2483:Moritz von Jacobi 2479:Heinrich von Wild 2350:thermal expansion 2236:explain that the 2123:French Revolution 2004:Mediterranean Sea 1928:Kingdom of Saxony 1587:Heinrich von Wild 1355:Giovanni Fabbroni 1339:Ligurian Republic 1331:Helvetic Republic 1299:Batavian Republic 1288:Salses-le-Chateau 1229:Montjuïc Fortress 1049:running south to 1017: 1016: 1012: 934:French Revolution 831:systematic errors 742:by combining the 579:theory of gravity 563:centrifugal force 488:toise universelle 431:Paris Observatory 354:Paris Observatory 256:in the background 254:Paris Observatory 241:Universal measure 90:French Revolution 16:(Redirected from 9937: 9911: 9903: 9883: 9882: 9867: 9857: 9851: 9850: 9836: 9825: 9824: 9815: 9809: 9808: 9766: 9760: 9759: 9712: 9706: 9705: 9688: 9682: 9681: 9643: 9637: 9636: 9598: 9592: 9591: 9560: 9551: 9550: 9539:10.1038/187493a0 9512: 9506: 9505: 9475: 9469: 9468: 9467: 9465: 9459:Nobel Foundation 9449: 9443: 9442: 9417:(9): S469–S495. 9406: 9397: 9388: 9387: 9368: 9362: 9361: 9335: 9329: 9328: 9317:Michelson, A. A. 9313: 9307: 9305: 9300: 9294: 9293: 9291: 9289: 9274: 9268: 9267: 9247: 9241: 9240: 9238: 9236: 9220: 9214: 9213: 9189: 9183: 9182: 9164: 9162:10.1038/134874b0 9133: 9127: 9126: 9124: 9122: 9117:on 30 April 2017 9113:. Archived from 9103: 9097: 9096: 9088: 9082: 9081: 9069: 9063: 9062: 9047: 9041: 9040: 9038: 9027: 9021: 9020: 8992: 8986: 8985: 8984: 8982: 8976: 8959: 8945: 8936: 8935: 8905: 8896: 8895: 8894: 8892: 8883:, archived from 8871: 8865: 8864: 8862: 8860: 8844: 8835: 8832:Metre Convention 8828: 8822: 8821: 8811: 8779: 8773: 8772: 8771:. 30 March 1875. 8761: 8755: 8754: 8746: 8737: 8736: 8726: 8720: 8719: 8710: 8704: 8703: 8659: 8653: 8652: 8650: 8648: 8634: 8628: 8627: 8626: 8624: 8608: 8593: 8592: 8591: 8589: 8575: 8569: 8568: 8562: 8553: 8547: 8542: 8533: 8532: 8524: 8517: 8508: 8507: 8495: 8489: 8488: 8486: 8484: 8468: 8462: 8461: 8459: 8435: 8429: 8428: 8426: 8424: 8410: 8401: 8400: 8398: 8396: 8382: 8376: 8375: 8373: 8371: 8361: 8352: 8343: 8342: 8294: 8288: 8287: 8255: 8246: 8245: 8235: 8229: 8228: 8188: 8182: 8181: 8179: 8177: 8163: 8157: 8150: 8144: 8143: 8141: 8139: 8112: 8106: 8105: 8103: 8101: 8085: 8079: 8078: 8076: 8074: 8055: 8049: 8048: 8039: 8033: 8027: 8021: 8020: 8002: 7993: 7992: 7990: 7988: 7975: 7966: 7965: 7945: 7939: 7938: 7920: 7914: 7913: 7907: 7899: 7890: 7884: 7883: 7877: 7869: 7859: 7853: 7852: 7842: 7836: 7835: 7833: 7823: 7814: 7813: 7765: 7759: 7758: 7740: 7708: 7699: 7698: 7696: 7694: 7667: 7661: 7660: 7612: 7606: 7605: 7571: 7560: 7559: 7557: 7555: 7541: 7535: 7534: 7502: 7496: 7495: 7485: 7461: 7455: 7454: 7448: 7440: 7430: 7424: 7423: 7417: 7409: 7399: 7393: 7392: 7390: 7388: 7375: 7369: 7362: 7353: 7352: 7342: 7336: 7335: 7325: 7319: 7318: 7316: 7314: 7299: 7293: 7292: 7291: 7289: 7273: 7267: 7266: 7264: 7262: 7235: 7224: 7223: 7216: 7207: 7206: 7186: 7180: 7173: 7167: 7166: 7164: 7162: 7146: 7140: 7139: 7113: 7081: 7070: 7069: 7067: 7059: 7053: 7052: 7046: 7038: 7029: 7023: 7022: 7016: 7008: 6998: 6992: 6991: 6981: 6975: 6974: 6934: 6928: 6927: 6925: 6909: 6900: 6899: 6893: 6885: 6874: 6868: 6867: 6861: 6853: 6843: 6834: 6833: 6823: 6817: 6816: 6810: 6802: 6774: 6763: 6757: 6751: 6750: 6748: 6746: 6735:"Wild, Heinrich" 6731: 6725: 6724: 6722: 6720: 6705:"History of IMO" 6701: 6695: 6694: 6669: 6663: 6662: 6652: 6635:(1): 31–32, 36. 6620: 6611: 6610: 6609: 6592: 6583: 6582: 6550: 6541: 6540: 6530: 6524: 6523: 6517: 6509: 6498: 6492: 6491: 6473: 6441: 6432: 6431: 6429: 6427: 6413: 6407: 6406: 6404: 6402: 6386: 6380: 6379: 6369: 6363: 6362: 6360: 6358: 6342: 6336: 6335: 6303: 6290: 6287: 6281: 6280: 6274: 6266: 6257: 6251: 6250: 6232: 6226: 6225: 6207: 6198: 6197: 6195: 6193: 6176: 6170: 6169: 6167: 6165: 6153: 6147: 6146: 6106: 6100: 6099: 6097: 6095: 6072: 6066: 6063: 6057: 6056: 6054: 6052: 6040:Ramani, Madhvi. 6037: 6031: 6030: 6010: 6004: 6003: 6001: 5999: 5983: 5977: 5976: 5974: 5972: 5956: 5950: 5949: 5943: 5935: 5924: 5918: 5917: 5915: 5913: 5899: 5893: 5892: 5860: 5854: 5853: 5843: 5837: 5836: 5834: 5832: 5818: 5812: 5811: 5774: 5768: 5767: 5757: 5733: 5727: 5726: 5720: 5715: 5713: 5705: 5697: 5691: 5690: 5680: 5656: 5650: 5649: 5629: 5623: 5622: 5612: 5580: 5571: 5570: 5568: 5558: 5549: 5548: 5547: 5530: 5524: 5523: 5521: 5519: 5503: 5497: 5492:Adolphe Hirsch, 5490: 5484: 5483: 5477: 5468: 5462: 5461: 5459: 5457: 5441: 5435: 5434: 5409: 5403: 5402: 5396: 5394: 5373: 5367: 5366: 5364: 5349: 5348: 5343: 5337: 5336: 5304: 5298: 5297: 5295: 5278:Viik, T (2006). 5275: 5269: 5268: 5266: 5264: 5248: 5242: 5241: 5235: 5227: 5216: 5210: 5209: 5207: 5205: 5178: 5172: 5171: 5143: 5137: 5136: 5134: 5132: 5118: 5112: 5111: 5093: 5087: 5086: 5078: 5071: 5065: 5064: 5054: 5034: 5028: 5027: 4999: 4993: 4992: 4960: 4954: 4953: 4945: 4934: 4925: 4924: 4918: 4916: 4899: 4893: 4892: 4890: 4888: 4873: 4867: 4866: 4864: 4862: 4847: 4841: 4840: 4838: 4836: 4821: 4815: 4814: 4784: 4778: 4777: 4771: 4769: 4747: 4738: 4737: 4736: 4734: 4728: 4717: 4705: 4699: 4698: 4691: 4685: 4684: 4682: 4680: 4666: 4660: 4659: 4657: 4655: 4640: 4634: 4633: 4619: 4613: 4612: 4586: 4580: 4579: 4562: 4556: 4555: 4529: 4523: 4522: 4508: 4497: 4491: 4485: 4484: 4474: 4468: 4467: 4457: 4449: 4423: 4417: 4416: 4387: 4378: 4377: 4375: 4373: 4359: 4353: 4352: 4350: 4348: 4333: 4327: 4326: 4316: 4315: 4310: 4299: 4298: 4290: 4284: 4283: 4273: 4264: 4258: 4257: 4233: 4227: 4226: 4224: 4216: 4210: 4209: 4181: 4172: 4149: 4148: 4135: 4126: 4125: 4123: 4121: 4116:on 30 April 2017 4112:. Archived from 4102: 4096: 4095: 4093: 4091: 4082:. Archived from 4072: 4056: 4054: 4043: 4039: 4034: 4028: 4026: 4022: 4017: 4011: 4009: 3996: 3990: 3986: 3980: 3971: 3970: 3968: 3967: 3966: 3964: 3959: 3958: 3953: 3948: 3945: 3944: 3943: 3940: 3927: 3926: 3924: 3923: 3922: 3920: 3915: 3914: 3909: 3904: 3901: 3900: 3899: 3896: 3886: 3885: 3883: 3882: 3881: 3879: 3874: 3873: 3868: 3863: 3860: 3859: 3858: 3855: 3844: 3838: 3836: 3829: 3821: 3815: = 12 3813: 3805: 3797: = 12 3795: 3787: 3777: 3767: 3764:mesures usuelles 3758: 3750: 3743: 3737: 3729: 3723: 3721: 3719: 3718: 3713: 3711: 3710: 3709: 3680: 3678: 3677: 3672: 3670: 3663: 3656: 3655: 3651: 3629: 3627: 3626: 3621: 3616: 3615: 3610: 3606: 3601: 3600: 3596: 3583: 3559: 3557: 3556: 3551: 3549: 3548: 3544: 3524: 3522: 3521: 3516: 3511: 3502: 3501: 3479: 3473: 3471: 3470: 3467: 3464: 3453: 3447: 3445: 3444: 3437: 3389: 3379: 3378: 3374: 3361: 3325: 3303: 3289: 3281:First prototype 3272: 3251: 3250: 3246: 3222: 3218: 3196: 3186: 3185: 3182: 3176: 3164: 3163: 3159: 3142: 3115: 3030:refractive index 3010: 2972:Krypton standard 2927: 2923: 2922: 2918: 2880:Jean-René Benoît 2840:changed that of 2794:, who following 2721: 2713: 2698: 2696: 2695: 2687: 2653: 2642: 2563:Metre Convention 2541: 2525: 2513:Metre Convention 2495:Paris Conference 2270: 2262: 2197:defeated in the 2143:Hispanic America 2099: 1936:Kingdom of Italy 1853:repeating circle 1835: 1823:repeating circle 1757:would be. After 1728:Shetland Islands 1589:would represent 1473: 1472: 1469: 1462: 1460: 1459: 1456: 1453: 1405: 1327:Kingdom of Spain 1281: 1267: 1261: 1255: 1247: 1239: 1203: 1168: 1167: 1163: 1153:and another in " 1147:repeating circle 1128:Repeating circle 1105:Balearic Islands 1008: 988: 987: 980: 960:seconds pendulum 948:Thomas Jefferson 916: 863:Metre Convention 856: 854: 853: 850: 847: 819:Emile Plantamour 793: 791: 790: 787: 784: 765: 763: 762: 759: 756: 741: 739: 738: 735: 732: 725: 723: 722: 719: 716: 705: 703: 702: 699: 696: 685: 683: 682: 679: 676: 648: 619:with variant of 567:seconds pendulum 546: 501: 490: 480: 468: 456: 449:is defined as 6 448: 427:seconds pendulum 389:seconds pendulum 228: 218: 217: 214: 208: 180:platinum-iridium 173: 157:Metre Convention 142: 131: 129: 128: 125: 122: 102:seconds pendulum 83: 68:starts with the 21: 9945: 9944: 9940: 9939: 9938: 9936: 9935: 9934: 9915: 9914: 9891: 9886: 9879: 9858: 9854: 9837: 9828: 9817: 9816: 9812: 9772: 9767: 9763: 9713: 9709: 9690: 9689: 9685: 9644: 9640: 9599: 9595: 9561: 9554: 9513: 9509: 9476: 9472: 9463: 9461: 9451: 9450: 9446: 9404: 9398: 9391: 9370: 9369: 9365: 9336: 9332: 9314: 9310: 9303: 9301: 9297: 9287: 9285: 9276: 9275: 9271: 9264: 9248: 9244: 9234: 9232: 9221: 9217: 9190: 9186: 9135: 9134: 9130: 9120: 9118: 9105: 9104: 9100: 9089: 9085: 9080:on 4 June 2024. 9070: 9066: 9049: 9048: 9044: 9036: 9028: 9024: 8993: 8989: 8980: 8978: 8974: 8968: 8957: 8946: 8939: 8906: 8899: 8890: 8888: 8873: 8872: 8868: 8858: 8856: 8845: 8838: 8829: 8825: 8780: 8776: 8763: 8762: 8758: 8747: 8740: 8727: 8723: 8712: 8711: 8707: 8660: 8656: 8646: 8644: 8636: 8635: 8631: 8622: 8620: 8610: 8609: 8596: 8587: 8585: 8576: 8572: 8560: 8554: 8550: 8543: 8536: 8519: 8518: 8511: 8496: 8492: 8482: 8480: 8469: 8465: 8436: 8432: 8422: 8420: 8412: 8411: 8404: 8394: 8392: 8384: 8383: 8379: 8369: 8367: 8366:. pp. 4, 8 8359: 8353: 8346: 8295: 8291: 8256: 8249: 8236: 8232: 8189: 8185: 8175: 8173: 8165: 8164: 8160: 8151: 8147: 8137: 8135: 8113: 8109: 8099: 8097: 8086: 8082: 8072: 8070: 8057: 8056: 8052: 8041: 8040: 8036: 8028: 8024: 8003: 7996: 7986: 7984: 7977: 7976: 7969: 7962: 7946: 7942: 7935: 7921: 7917: 7901: 7900: 7891: 7887: 7871: 7870: 7860: 7856: 7843: 7839: 7831: 7825: 7824: 7817: 7766: 7762: 7709: 7702: 7692: 7690: 7668: 7664: 7613: 7609: 7602: 7572: 7563: 7553: 7551: 7543: 7542: 7538: 7503: 7499: 7462: 7458: 7442: 7441: 7431: 7427: 7411: 7410: 7400: 7396: 7386: 7384: 7377: 7376: 7372: 7363: 7356: 7343: 7339: 7326: 7322: 7312: 7310: 7300: 7296: 7287: 7285: 7274: 7270: 7260: 7258: 7236: 7227: 7218: 7217: 7210: 7203: 7187: 7183: 7174: 7170: 7160: 7158: 7147: 7143: 7111:10.1.1.492.3967 7082: 7073: 7065: 7061: 7060: 7056: 7040: 7039: 7030: 7026: 7010: 7009: 6999: 6995: 6982: 6978: 6935: 6931: 6923:10.1.1.517.9501 6910: 6903: 6887: 6886: 6875: 6871: 6855: 6854: 6844: 6837: 6824: 6820: 6804: 6803: 6791: 6775: 6766: 6758: 6754: 6744: 6742: 6733: 6732: 6728: 6718: 6716: 6703: 6702: 6698: 6683: 6671: 6670: 6666: 6621: 6614: 6593: 6586: 6551: 6544: 6531: 6527: 6511: 6510: 6499: 6495: 6442: 6435: 6425: 6423: 6415: 6414: 6410: 6400: 6398: 6387: 6383: 6370: 6366: 6356: 6354: 6343: 6339: 6304: 6293: 6288: 6284: 6268: 6267: 6258: 6254: 6247: 6233: 6229: 6222: 6208: 6201: 6191: 6189: 6186:The Century Co. 6177: 6173: 6163: 6161: 6154: 6150: 6107: 6103: 6093: 6091: 6073: 6069: 6064: 6060: 6050: 6048: 6038: 6034: 6027: 6011: 6007: 5997: 5995: 5984: 5980: 5970: 5968: 5957: 5953: 5937: 5936: 5925: 5921: 5911: 5909: 5901: 5900: 5896: 5861: 5857: 5844: 5840: 5830: 5828: 5820: 5819: 5815: 5775: 5771: 5734: 5730: 5718: 5716: 5707: 5706: 5698: 5694: 5657: 5653: 5646: 5630: 5626: 5581: 5574: 5566: 5560: 5559: 5552: 5531: 5527: 5517: 5515: 5504: 5500: 5491: 5487: 5475: 5469: 5465: 5455: 5453: 5442: 5438: 5423: 5411: 5410: 5406: 5392: 5390: 5375: 5374: 5370: 5362: 5346: 5344: 5340: 5319:(7–8): 97–116. 5305: 5301: 5293:10.1.1.517.9501 5276: 5272: 5262: 5260: 5249: 5245: 5229: 5228: 5217: 5213: 5203: 5201: 5179: 5175: 5144: 5140: 5130: 5128: 5120: 5119: 5115: 5108: 5094: 5090: 5073: 5072: 5068: 5035: 5031: 5016: 5000: 4996: 4961: 4957: 4935: 4928: 4914: 4912: 4900: 4896: 4886: 4884: 4875: 4874: 4870: 4860: 4858: 4849: 4848: 4844: 4834: 4832: 4823: 4822: 4818: 4803: 4785: 4781: 4767: 4765: 4755:Arago, François 4748: 4741: 4732: 4730: 4729:on 20 June 2019 4726: 4715: 4706: 4702: 4693: 4692: 4688: 4678: 4676: 4667: 4663: 4653: 4651: 4642: 4641: 4637: 4620: 4616: 4601: 4587: 4583: 4563: 4559: 4544: 4530: 4526: 4509: 4500: 4492: 4488: 4475: 4471: 4451: 4450: 4438: 4424: 4420: 4405: 4388: 4381: 4371: 4369: 4361: 4360: 4356: 4346: 4344: 4334: 4330: 4313: 4311: 4302: 4291: 4287: 4271: 4265: 4261: 4234: 4230: 4222: 4218: 4217: 4213: 4179: 4173: 4152: 4137: 4136: 4129: 4119: 4117: 4104: 4103: 4099: 4089: 4087: 4074: 4073: 4069: 4065: 4060: 4059: 4052: 4050: 4041: 4037: 4035: 4031: 4024: 4020: 4018: 4014: 4007: 3997: 3993: 3987: 3983: 3962: 3960: 3956: 3954: 3950: 3949: 3946: 3941: 3938: 3936: 3934: 3933: 3932: 3930:Rodez Cathedral 3919:Rodez Cathedral 3918: 3916: 3912: 3910: 3906: 3905: 3902: 3897: 3894: 3892: 3890: 3889: 3888: 3878:Belfry, Dunkirk 3877: 3875: 3871: 3869: 3865: 3864: 3861: 3856: 3853: 3851: 3849: 3848: 3847: 3845: 3841: 3831: = 1 3779: = 6 3744: 3740: 3730: 3726: 3705: 3701: 3694: 3686: 3683: 3682: 3666: 3647: 3643: 3639: 3637: 3634: 3633: 3611: 3592: 3588: 3584: 3582: 3578: 3577: 3566: 3563: 3562: 3540: 3536: 3532: 3530: 3527: 3526: 3500: 3486: 3483: 3482: 3480: 3476: 3468: 3465: 3462: 3460: 3455:Since 2012 the 3454: 3450: 3442: 3440: 3438: 3434: 3429: 3402: 3387: 3376: 3372: 3371: 3359: 3323: 3301: 3270: 3248: 3244: 3243: 3237: 3232: 3217: 3195: 3188: 3183: 3180: 3178: 3174: 3161: 3157: 3156: 3140: 3113: 3067: 3042: 3018: 3014: 3008: 2974: 2925: 2920: 2916: 2915: 2872:interferometric 2860: 2855: 2854: 2806:had questioned 2792:Albert Einstein 2783:application of 2744: 2693: 2691: 2690: 2679:Johnson Matthey 2559: 2558: 2360:, a second for 2333:Committee Meter 2284: 2187:standardization 2127:Napoleonic Wars 2119: 2114: 2113: 2088:First World War 1896:Austrian Empire 1836: 1833: 1755:Earth ellipsoid 1489: 1481: 1480: 1470: 1467: 1465: 1457: 1454: 1451: 1450: 1448: 1447:and a value of 1424: 1407: 1395:Gaspar de Prony 1367:Barnabé Brisson 1351:Tuscan Republic 1303:Henricus Aeneae 1221:Rodez Cathedral 1213:Rodez Cathedral 1165: 1161: 1160: 1061:Montjuïc Castle 1031: 1013: 989: 985: 978: 950:and others for 851: 848: 845: 844: 842: 788: 785: 782: 781: 779: 760: 757: 754: 753: 751: 736: 733: 730: 729: 727: 720: 717: 714: 713: 711: 700: 697: 694: 693: 691: 680: 677: 674: 673: 671: 641:Earth ellipsoid 629:Alexis Clairaut 595:oblate spheroid 535:radius of Earth 499:metro cattolico 243: 227: 220: 215: 212: 210: 206: 184:standardization 126: 123: 120: 119: 117: 28: 23: 22: 18:Prototype metre 15: 12: 11: 5: 9943: 9933: 9932: 9927: 9913: 9912: 9898:, ed. (1911). 9896:Chisholm, Hugh 9890: 9889:External links 9887: 9885: 9884: 9877: 9852: 9826: 9810: 9783:(3): 136–138. 9776:Optics Letters 9770: 9761: 9726:(3): 133–135. 9719:Optics Letters 9707: 9683: 9656:(3): 133–134. 9638: 9611:(4): 196–199. 9593: 9552: 9507: 9488:(5): 455–463. 9481:Applied Optics 9470: 9444: 9389: 9363: 9340:Fabry, Charles 9330: 9308: 9295: 9269: 9262: 9242: 9215: 9184: 9128: 9098: 9083: 9064: 9042: 9022: 9003:(5): 419–422. 8987: 8966: 8937: 8918:(6): 415–434. 8897: 8866: 8853:NobelPrize.org 8836: 8823: 8774: 8756: 8738: 8721: 8705: 8670:(9): 558–568. 8654: 8629: 8594: 8570: 8548: 8534: 8509: 8490: 8463: 8430: 8402: 8377: 8344: 8289: 8247: 8230: 8183: 8158: 8145: 8107: 8080: 8050: 8034: 8030:Bigourdan 1901 8022: 7994: 7967: 7960: 7940: 7933: 7915: 7885: 7854: 7837: 7815: 7760: 7700: 7662: 7627:(3): 248–313. 7607: 7600: 7561: 7536: 7497: 7456: 7425: 7394: 7370: 7354: 7337: 7320: 7294: 7268: 7250:(7): 377–378. 7225: 7208: 7201: 7181: 7168: 7141: 7096:(3): 176–188. 7071: 7054: 7024: 6993: 6976: 6929: 6901: 6869: 6835: 6818: 6789: 6764: 6752: 6739:hls-dhs-dss.ch 6726: 6709:public.wmo.int 6696: 6681: 6664: 6612: 6584: 6565:(2): 117–129. 6542: 6525: 6493: 6433: 6408: 6395:FranceArchives 6381: 6378:. p. 163. 6364: 6337: 6291: 6282: 6252: 6246:978-0349115078 6245: 6227: 6220: 6199: 6188:pp. 10–11 6171: 6148: 6121:(4): 355–372. 6101: 6067: 6058: 6032: 6025: 6005: 5978: 5965:FranceArchives 5951: 5919: 5894: 5855: 5838: 5813: 5769: 5728: 5719:|journal= 5692: 5671:(4): 355–372. 5651: 5644: 5624: 5572: 5550: 5525: 5498: 5485: 5463: 5436: 5421: 5404: 5368: 5338: 5299: 5270: 5243: 5211: 5173: 5138: 5113: 5106: 5088: 5066: 5029: 5014: 4994: 4955: 4940:, ed. (1911). 4938:Chisholm, Hugh 4926: 4894: 4868: 4842: 4816: 4801: 4779: 4739: 4700: 4686: 4661: 4635: 4614: 4599: 4581: 4557: 4542: 4524: 4498: 4494:Bigourdan 1901 4486: 4483:. p. 403. 4469: 4436: 4418: 4403: 4379: 4354: 4328: 4300: 4285: 4259: 4248:(3): 352–356. 4228: 4211: 4192:(9): 596–613. 4150: 4127: 4097: 4066: 4064: 4061: 4058: 4057: 4048: 4029: 4012: 4002:) defined the 3991: 3981: 3839: 3823:; so 864 3755:toise de Pérou 3745:All values in 3738: 3724: 3708: 3704: 3700: 3697: 3693: 3690: 3669: 3662: 3659: 3654: 3650: 3646: 3642: 3631: 3630: 3619: 3614: 3609: 3604: 3599: 3595: 3591: 3587: 3581: 3576: 3573: 3570: 3547: 3543: 3539: 3535: 3514: 3508: 3505: 3499: 3496: 3493: 3490: 3474: 3448: 3431: 3430: 3428: 3425: 3424: 3423: 3418: 3413: 3408: 3401: 3398: 3395: 3394: 3391: 3384: 3381: 3367: 3366: 3363: 3356: 3353: 3345: 3344: 3341: 3338: 3335: 3331: 3330: 3327: 3320: 3317: 3309: 3308: 3305: 3298: 3295: 3278: 3277: 3274: 3267: 3264: 3240: 3239: 3234: 3229: 3226: 3216: 3213: 3199: 3198: 3193: 3167: 3166: 3106:speed of light 3041: 3038: 3016: 3012: 2986:Doppler effect 2973: 2970: 2859: 2856: 2810:in 1687 after 2745: 2737: 2671:Tresca section 2619:Adolphe Hirsch 2329:Étienne Lenoir 2307:At that time, 2293:Johnson Mattey 2285: 2277: 2246:Adolphe Hirsch 2171:Ottoman Empire 2118: 2115: 2084:British Empire 2020:Central Europe 1944:Russian Empire 1892:Central Europe 1865:Leonhard Euler 1831: 1740:Paris meridian 1637:canton of Bern 1618:Paris meridian 1610:Louis Puissant 1490: 1482: 1425: 1417: 1406: 1399: 1379:René Just Haüy 1347:Roman Republic 1182:Pierre Méchain 1143:decimalisation 1136:Étienne Lenoir 1113:François Arago 1015: 1014: 992: 990: 983: 977: 974: 923:British Empire 914:Toise de Paris 835:Adolphe Hirsch 561:found out the 531:solar parallax 423:Paris meridian 358:Paris meridian 289:cubit into 28 281:. Indeed, the 242: 239: 231: 230: 225: 196:speed of light 42:Earth quadrant 26: 9: 6: 4: 3: 2: 9942: 9931: 9928: 9926: 9923: 9922: 9920: 9909: 9908: 9902: 9897: 9893: 9892: 9880: 9874: 9871: 9866: 9865: 9856: 9848: 9847: 9846:New Scientist 9842: 9835: 9833: 9831: 9822: 9821: 9814: 9806: 9802: 9798: 9794: 9790: 9786: 9782: 9778: 9777: 9765: 9757: 9753: 9749: 9745: 9741: 9737: 9733: 9729: 9725: 9721: 9720: 9711: 9703: 9699: 9695: 9694: 9687: 9679: 9675: 9671: 9667: 9663: 9659: 9655: 9651: 9650: 9642: 9634: 9630: 9626: 9622: 9618: 9614: 9610: 9606: 9605: 9597: 9589: 9585: 9581: 9577: 9573: 9569: 9568: 9559: 9557: 9548: 9544: 9540: 9536: 9532: 9528: 9524: 9520: 9519: 9511: 9503: 9499: 9495: 9491: 9487: 9483: 9482: 9474: 9460: 9456: 9455: 9448: 9440: 9436: 9432: 9428: 9424: 9420: 9416: 9412: 9411: 9403: 9396: 9394: 9386: 9382: 9378: 9375:(in French). 9374: 9367: 9359: 9356:(in French). 9355: 9354: 9349: 9345: 9341: 9334: 9326: 9323:(in French). 9322: 9318: 9312: 9299: 9283: 9279: 9273: 9265: 9259: 9255: 9254: 9246: 9230: 9226: 9219: 9211: 9207: 9203: 9199: 9195: 9188: 9180: 9176: 9172: 9168: 9163: 9158: 9154: 9150: 9146: 9142: 9138: 9132: 9116: 9112: 9108: 9102: 9094: 9087: 9079: 9075: 9068: 9061: 9056: 9052: 9046: 9035: 9034: 9026: 9018: 9014: 9010: 9006: 9002: 8998: 8991: 8973: 8969: 8967:92-822-2213-6 8963: 8956: 8955: 8950: 8944: 8942: 8933: 8929: 8925: 8921: 8917: 8913: 8912: 8904: 8902: 8886: 8882: 8878: 8877: 8870: 8855:. p. 448 8854: 8850: 8843: 8841: 8833: 8827: 8819: 8815: 8810: 8805: 8801: 8797: 8793: 8789: 8785: 8778: 8770: 8766: 8760: 8752: 8745: 8743: 8734: 8733: 8725: 8717: 8716: 8709: 8701: 8697: 8693: 8689: 8685: 8681: 8677: 8673: 8669: 8665: 8658: 8643: 8639: 8633: 8619: 8615: 8614: 8607: 8605: 8603: 8601: 8599: 8583: 8582: 8574: 8566: 8559: 8552: 8546: 8541: 8539: 8530: 8529: 8523: 8516: 8514: 8505: 8501: 8494: 8478: 8474: 8467: 8458: 8453: 8449: 8445: 8441: 8434: 8419: 8415: 8409: 8407: 8391: 8387: 8381: 8365: 8358: 8351: 8349: 8340: 8336: 8332: 8328: 8324: 8320: 8316: 8312: 8309:(12): 39–44. 8308: 8304: 8303:Physics Today 8300: 8293: 8285: 8281: 8277: 8273: 8269: 8265: 8261: 8254: 8252: 8243: 8242: 8234: 8226: 8222: 8218: 8214: 8210: 8206: 8202: 8198: 8194: 8187: 8172: 8168: 8162: 8155: 8149: 8134: 8130: 8126: 8123:(in German). 8122: 8118: 8111: 8095: 8091: 8084: 8068: 8064: 8060: 8054: 8046: 8045: 8038: 8031: 8026: 8018: 8014: 8010: 8009: 8001: 7999: 7982: 7981: 7974: 7972: 7963: 7957: 7953: 7952: 7944: 7936: 7930: 7926: 7919: 7911: 7905: 7898: 7897: 7889: 7881: 7875: 7867: 7866: 7858: 7850: 7849: 7841: 7830: 7829: 7822: 7820: 7811: 7807: 7803: 7799: 7795: 7791: 7787: 7783: 7779: 7775: 7771: 7764: 7756: 7752: 7748: 7744: 7739: 7734: 7730: 7726: 7722: 7718: 7714: 7707: 7705: 7689: 7685: 7681: 7678:(in French). 7677: 7673: 7666: 7658: 7654: 7650: 7646: 7642: 7638: 7634: 7630: 7626: 7623:(in French). 7622: 7618: 7611: 7603: 7597: 7593: 7589: 7585: 7581: 7580:IAG 150 Years 7577: 7570: 7568: 7566: 7550: 7546: 7540: 7532: 7528: 7524: 7520: 7516: 7512: 7508: 7501: 7493: 7489: 7484: 7479: 7475: 7471: 7467: 7460: 7452: 7446: 7438: 7437: 7429: 7421: 7415: 7407: 7406: 7398: 7383: 7380: 7374: 7367: 7361: 7359: 7350: 7349: 7341: 7333: 7332: 7324: 7309: 7305: 7298: 7283: 7279: 7272: 7257: 7253: 7249: 7246:(in French). 7245: 7241: 7234: 7232: 7230: 7221: 7215: 7213: 7204: 7198: 7194: 7193: 7185: 7178: 7172: 7156: 7152: 7145: 7137: 7133: 7129: 7125: 7121: 7117: 7112: 7107: 7103: 7099: 7095: 7091: 7087: 7080: 7078: 7076: 7064: 7058: 7050: 7044: 7037: 7036: 7028: 7020: 7014: 7006: 7005: 6997: 6989: 6988: 6980: 6972: 6968: 6964: 6960: 6956: 6952: 6948: 6944: 6940: 6933: 6924: 6919: 6915: 6908: 6906: 6897: 6891: 6883: 6882: 6873: 6865: 6859: 6851: 6850: 6842: 6840: 6831: 6830: 6822: 6814: 6808: 6800: 6796: 6792: 6786: 6782: 6781: 6773: 6771: 6769: 6761: 6756: 6740: 6736: 6730: 6714: 6710: 6706: 6700: 6692: 6688: 6684: 6678: 6674: 6668: 6660: 6656: 6651: 6646: 6642: 6638: 6634: 6630: 6626: 6619: 6617: 6608: 6603: 6599: 6591: 6589: 6580: 6576: 6572: 6568: 6564: 6560: 6556: 6549: 6547: 6538: 6537: 6529: 6521: 6515: 6507: 6506: 6497: 6489: 6485: 6481: 6477: 6472: 6467: 6463: 6459: 6455: 6451: 6447: 6440: 6438: 6422: 6418: 6412: 6396: 6392: 6385: 6377: 6376: 6368: 6352: 6348: 6341: 6333: 6329: 6325: 6321: 6317: 6313: 6309: 6302: 6300: 6298: 6296: 6286: 6278: 6272: 6265: 6264: 6256: 6248: 6242: 6238: 6231: 6223: 6221:0-349-11507-9 6217: 6213: 6206: 6204: 6187: 6184: 6183: 6175: 6159: 6152: 6144: 6140: 6136: 6132: 6128: 6124: 6120: 6116: 6112: 6105: 6090: 6086: 6082: 6078: 6071: 6062: 6047: 6043: 6036: 6028: 6022: 6018: 6017: 6009: 5993: 5989: 5982: 5966: 5962: 5955: 5947: 5941: 5933: 5932: 5923: 5908: 5904: 5898: 5890: 5886: 5882: 5878: 5874: 5870: 5866: 5859: 5851: 5850: 5842: 5827: 5823: 5817: 5809: 5805: 5801: 5797: 5793: 5789: 5785: 5781: 5773: 5765: 5761: 5756: 5751: 5747: 5743: 5739: 5732: 5724: 5711: 5703: 5696: 5688: 5684: 5679: 5674: 5670: 5666: 5662: 5655: 5647: 5645:9780387755342 5641: 5637: 5636: 5628: 5620: 5616: 5611: 5606: 5602: 5598: 5594: 5590: 5586: 5579: 5577: 5565: 5564: 5557: 5555: 5546: 5541: 5537: 5529: 5513: 5509: 5502: 5495: 5489: 5481: 5474: 5467: 5451: 5447: 5440: 5432: 5428: 5424: 5418: 5414: 5408: 5400: 5388: 5384: 5383: 5378: 5372: 5361: 5360: 5353: 5352:public domain 5342: 5334: 5330: 5326: 5322: 5318: 5314: 5310: 5303: 5294: 5289: 5285: 5281: 5274: 5258: 5254: 5247: 5239: 5233: 5225: 5224: 5215: 5200: 5196: 5192: 5189:(in French). 5188: 5184: 5177: 5169: 5165: 5161: 5157: 5153: 5149: 5142: 5127: 5123: 5117: 5109: 5103: 5099: 5092: 5084: 5083: 5077: 5070: 5062: 5058: 5053: 5048: 5044: 5040: 5033: 5025: 5021: 5017: 5011: 5007: 5006: 4998: 4990: 4986: 4982: 4978: 4974: 4970: 4966: 4959: 4951: 4950: 4944: 4939: 4933: 4931: 4922: 4910: 4909: 4904: 4898: 4882: 4881:clea-astro.eu 4878: 4872: 4857:. p. 237 4856: 4852: 4846: 4830: 4826: 4820: 4812: 4808: 4804: 4802:9782804184964 4798: 4794: 4790: 4783: 4775: 4763: 4762: 4756: 4752: 4746: 4744: 4725: 4721: 4714: 4710: 4704: 4696: 4690: 4674: 4673: 4665: 4649: 4645: 4639: 4631: 4627: 4626: 4618: 4610: 4606: 4602: 4600:9782804184964 4596: 4592: 4585: 4577: 4573: 4572: 4567: 4561: 4553: 4549: 4545: 4539: 4535: 4528: 4520: 4516: 4515: 4507: 4505: 4503: 4495: 4490: 4482: 4481: 4473: 4465: 4461: 4455: 4447: 4443: 4439: 4437:9782804184964 4433: 4429: 4422: 4414: 4410: 4406: 4404:9782757824900 4400: 4396: 4392: 4386: 4384: 4368: 4364: 4358: 4343: 4339: 4332: 4324: 4323: 4309: 4307: 4305: 4296: 4289: 4281: 4277: 4270: 4263: 4255: 4251: 4247: 4243: 4239: 4232: 4221: 4215: 4207: 4203: 4199: 4195: 4191: 4187: 4186: 4178: 4171: 4169: 4167: 4165: 4163: 4161: 4159: 4157: 4155: 4146: 4142: 4141: 4134: 4132: 4115: 4111: 4107: 4101: 4085: 4081: 4077: 4071: 4067: 4047: 4033: 4016: 4005: 4001: 3995: 3985: 3979: 3975: 3969: 3931: 3925: 3884: 3843: 3835: 3830: 3828: 3822: 3820: 3814: 3812: 3806: 3804: 3803: 3796: 3794: 3788: 3786: 3785: 3778: 3776: 3775: 3768: 3766: 3765: 3757: 3756: 3749: 3742: 3735: 3728: 3706: 3702: 3698: 3695: 3691: 3688: 3660: 3657: 3652: 3648: 3644: 3640: 3617: 3612: 3607: 3602: 3597: 3593: 3589: 3585: 3579: 3574: 3571: 3568: 3561: 3560: 3545: 3541: 3537: 3533: 3512: 3506: 3503: 3497: 3494: 3491: 3488: 3478: 3458: 3452: 3436: 3432: 3422: 3419: 3417: 3414: 3412: 3409: 3407: 3404: 3403: 3392: 3385: 3382: 3369: 3368: 3364: 3357: 3354: 3351: 3347: 3346: 3342: 3339: 3336: 3333: 3332: 3328: 3321: 3318: 3315: 3311: 3310: 3306: 3299: 3296: 3294: 3291:platinum bar 3290: 3288: 3287: 3280: 3279: 3275: 3268: 3265: 3263: 3259: 3255: 3242: 3241: 3235: 3230: 3227: 3224: 3223: 3212: 3209: 3205: 3204:caesium clock 3192: 3172: 3171: 3170: 3154: 3153: 3152: 3150: 3144: 3138: 3134: 3130: 3126: 3122: 3117: 3111: 3107: 3101: 3099: 3095: 3091: 3086: 3084: 3080: 3076: 3072: 3066: 3059: 3058:Univ. Paris 6 3055: 3051: 3046: 3037: 3035: 3031: 3026: 3020: 3004: 3002: 2997: 2995: 2991: 2987: 2983: 2979: 2969: 2967: 2963: 2959: 2954: 2952: 2947: 2941: 2939: 2933: 2931: 2913: 2909: 2905: 2901: 2897: 2893: 2889: 2885: 2881: 2877: 2873: 2864: 2851: 2847: 2843: 2839: 2835: 2831: 2827: 2824:Furthermore, 2823: 2821: 2820:French Guiana 2817: 2813: 2809: 2805: 2801: 2797: 2793: 2788: 2786: 2782: 2781:technological 2778: 2774: 2770: 2766: 2762: 2758: 2749: 2742: 2736: 2734: 2730: 2729:Bessel points 2724: 2722: 2720: 2714: 2712: 2704: 2700: 2688: 2686: 2680: 2676: 2672: 2668: 2665:and 10% 2664: 2659: 2655: 2652: 2645: 2643: 2641: 2640: 2633: 2628: 2626: 2625: 2620: 2616: 2612: 2608: 2604: 2600: 2599:German Empire 2596: 2592: 2588: 2587:meteorologist 2584: 2580: 2576: 2572: 2568: 2564: 2556: 2552: 2548: 2547: 2542: 2540: 2534: 2530: 2526: 2524: 2518: 2514: 2510: 2508: 2507:metric system 2504: 2500: 2496: 2490: 2488: 2487:metric system 2484: 2480: 2476: 2472: 2467: 2465: 2460: 2450: 2446: 2444: 2440: 2436: 2432: 2427: 2423: 2419: 2415: 2410: 2408: 2404: 2400: 2396: 2392: 2387: 2377: 2373: 2371: 2367: 2363: 2359: 2355: 2351: 2347: 2343: 2338: 2334: 2330: 2326: 2322: 2318: 2314: 2310: 2302: 2298: 2294: 2289: 2282: 2276: 2274: 2269: 2268: 2261: 2255: 2251: 2247: 2243: 2242:metric system 2239: 2235: 2231: 2226: 2224: 2220: 2216: 2212: 2211:German Empire 2208: 2204: 2200: 2196: 2192: 2188: 2185:and a better 2184: 2180: 2176: 2172: 2168: 2164: 2160: 2156: 2152: 2148: 2144: 2140: 2136: 2132: 2131:Latin America 2128: 2124: 2111: 2107: 2103: 2098: 2093: 2089: 2085: 2082:in 1889; and 2081: 2080:United-States 2077: 2073: 2069: 2065: 2061: 2059: 2055: 2051: 2047: 2043: 2039: 2038:French Empire 2035: 2031: 2027: 2023: 2021: 2017: 2013: 2009: 2005: 2001: 1997: 1993: 1989: 1985: 1981: 1977: 1973: 1968: 1963: 1961: 1957: 1954:, as well as 1953: 1949: 1945: 1941: 1937: 1933: 1929: 1925: 1921: 1917: 1913: 1909: 1905: 1901: 1897: 1893: 1889: 1885: 1880: 1878: 1874: 1870: 1866: 1863:predicted by 1862: 1858: 1854: 1850: 1841: 1830: 1824: 1820: 1816: 1812: 1808: 1804: 1800: 1796: 1792: 1788: 1784: 1780: 1776: 1772: 1768: 1764: 1760: 1756: 1752: 1748: 1741: 1737: 1733: 1729: 1724: 1720: 1718: 1714: 1710: 1706: 1702: 1698: 1694: 1690: 1686: 1681: 1677: 1673: 1669: 1665: 1660: 1657:district, in 1656: 1652: 1648: 1642: 1638: 1634: 1629: 1625: 1623: 1619: 1615: 1611: 1607: 1603: 1598: 1596: 1592: 1588: 1584: 1580: 1576: 1575: 1569: 1565: 1561: 1557: 1553: 1549: 1545: 1541: 1537: 1533: 1528: 1526: 1522: 1521:United States 1517: 1515: 1511: 1507: 1499: 1498:New York City 1494: 1487: 1478: 1446: 1441: 1440:triangulation 1437: 1433: 1429: 1422: 1411: 1404: 1398: 1396: 1392: 1388: 1384: 1380: 1376: 1372: 1368: 1364: 1360: 1356: 1352: 1348: 1344: 1340: 1336: 1332: 1328: 1324: 1320: 1316: 1312: 1308: 1304: 1300: 1295: 1293: 1289: 1285: 1280: 1275: 1271: 1266: 1260: 1254: 1253: 1246: 1245: 1238: 1232: 1230: 1226: 1222: 1214: 1209: 1205: 1202: 1201: 1195: 1191: 1187: 1183: 1179: 1174: 1172: 1158: 1157: 1152: 1148: 1144: 1137: 1133: 1129: 1125: 1121: 1119: 1114: 1110: 1106: 1102: 1098: 1094: 1090: 1086: 1082: 1078: 1074: 1066: 1062: 1058: 1052: 1048: 1044: 1040: 1035: 1030: 1026: 1022: 1011: 1010:(August 2020) 1006: 1002: 1001: 996: 991: 982: 981: 973: 970: 965: 961: 957: 956:British Crown 953: 949: 945: 940: 935: 931: 926: 924: 920: 915: 910: 906: 902: 898: 894: 887: 882: 878: 876: 872: 868: 864: 860: 840: 836: 832: 828: 824: 820: 816: 812: 811:Adolf Repsold 807: 805: 801: 797: 777: 776:least squares 773: 769: 749: 745: 709: 689: 669: 664: 660: 656: 652: 647: 642: 638: 634: 630: 627:According to 622: 618: 614: 610: 608: 604: 600: 596: 592: 588: 584: 580: 576: 572: 568: 564: 560: 556: 554: 550: 545: 540: 536: 532: 528: 527:French Guiana 524: 520: 516: 512: 510: 506: 502: 500: 494: 489: 484: 479: 478: 473:] or 864 472: 467: 466: 460: 455: 454: 447: 446: 440: 436: 432: 428: 424: 420: 419:triangulation 416: 412: 408: 404: 400: 398: 394: 390: 386: 382: 378: 374: 370: 366: 359: 355: 350: 346: 344: 340: 337:included six 336: 332: 328: 323: 319: 316:to 5 feet. A 315: 311: 307: 303: 299: 294: 292: 288: 284: 280: 276: 272: 268: 263: 255: 251: 247: 238: 236: 224: 205: 201: 200: 199: 197: 193: 188: 185: 181: 177: 172: 171: 164: 162: 158: 154: 150: 146: 141: 140: 133: 115: 111: 107: 103: 99: 95: 94:Ancien Régime 91: 86: 82: 81: 75: 71: 67: 59: 55: 51: 47: 43: 39: 34: 30: 19: 9905: 9863: 9855: 9844: 9819: 9813: 9780: 9774: 9764: 9723: 9717: 9710: 9692: 9686: 9653: 9647: 9641: 9608: 9602: 9596: 9571: 9565: 9522: 9516: 9510: 9485: 9479: 9473: 9462:, retrieved 9453: 9447: 9414: 9408: 9376: 9372: 9366: 9360:: 1082–1086. 9357: 9351: 9333: 9324: 9320: 9311: 9306:, p. 816–817 9298: 9286:. Retrieved 9281: 9272: 9252: 9245: 9233:. Retrieved 9228: 9218: 9201: 9197: 9187: 9144: 9140: 9131: 9119:. Retrieved 9115:the original 9111:www.bipm.org 9110: 9101: 9092: 9086: 9078:the original 9067: 9058: 9054: 9045: 9032: 9025: 9000: 8996: 8990: 8979:, retrieved 8953: 8915: 8909: 8889:, retrieved 8885:the original 8875: 8869: 8857:. Retrieved 8852: 8826: 8791: 8787: 8777: 8768: 8759: 8750: 8731: 8724: 8714: 8708: 8667: 8663: 8657: 8647:19 September 8645:. Retrieved 8642:IAG Homepage 8641: 8632: 8621:, retrieved 8612: 8588:20 September 8586:, retrieved 8580: 8573: 8564: 8551: 8526: 8503: 8499: 8493: 8481:. Retrieved 8476: 8466: 8447: 8443: 8433: 8421:. Retrieved 8418:IAG Homepage 8417: 8393:. Retrieved 8390:www.bipm.org 8389: 8380: 8368:. Retrieved 8363: 8306: 8302: 8292: 8267: 8264:L'Astronomie 8263: 8240: 8233: 8200: 8196: 8186: 8174:. Retrieved 8170: 8161: 8153: 8148: 8136:. Retrieved 8124: 8120: 8110: 8098:. Retrieved 8093: 8083: 8071:. Retrieved 8067:the original 8062: 8053: 8043: 8037: 8025: 8007: 7985:. Retrieved 7979: 7950: 7943: 7924: 7918: 7895: 7888: 7864: 7857: 7847: 7840: 7827: 7777: 7773: 7763: 7720: 7716: 7691:. Retrieved 7679: 7675: 7665: 7624: 7620: 7610: 7583: 7579: 7552:. Retrieved 7548: 7539: 7514: 7510: 7500: 7473: 7469: 7459: 7435: 7428: 7408:p. 419. 7404: 7397: 7385:. Retrieved 7381: 7373: 7365: 7347: 7340: 7330: 7323: 7311:. Retrieved 7307: 7297: 7286:, retrieved 7281: 7271: 7259:. Retrieved 7247: 7243: 7191: 7184: 7176: 7171: 7159:. Retrieved 7154: 7144: 7093: 7089: 7057: 7034: 7027: 7003: 6996: 6986: 6979: 6946: 6942: 6932: 6913: 6879: 6872: 6848: 6828: 6821: 6779: 6759: 6755: 6743:. Retrieved 6738: 6729: 6717:. Retrieved 6713:the original 6708: 6699: 6672: 6667: 6632: 6628: 6597: 6562: 6558: 6535: 6528: 6505:Delambre,... 6503: 6496: 6453: 6449: 6424:. Retrieved 6420: 6411: 6399:. Retrieved 6394: 6384: 6374: 6367: 6355:. Retrieved 6350: 6340: 6315: 6311: 6285: 6262: 6255: 6236: 6230: 6211: 6190:. Retrieved 6181: 6174: 6162:. Retrieved 6151: 6118: 6114: 6104: 6092:. Retrieved 6080: 6070: 6061: 6049:. Retrieved 6045: 6035: 6015: 6008: 5996:. Retrieved 5991: 5981: 5969:. Retrieved 5964: 5954: 5929: 5922: 5910:. Retrieved 5906: 5897: 5872: 5869:L'Astronomie 5868: 5858: 5848: 5841: 5829:. Retrieved 5825: 5816: 5783: 5779: 5772: 5745: 5741: 5731: 5710:cite journal 5695: 5668: 5664: 5654: 5634: 5627: 5592: 5588: 5562: 5535: 5528: 5516:. Retrieved 5511: 5501: 5493: 5488: 5479: 5466: 5454:. Retrieved 5449: 5439: 5412: 5407: 5397:– via 5391:. Retrieved 5386: 5380: 5371: 5358: 5341: 5316: 5312: 5302: 5283: 5273: 5261:. Retrieved 5256: 5246: 5223:Delambre,... 5221: 5214: 5202:. Retrieved 5190: 5186: 5176: 5151: 5147: 5141: 5129:. Retrieved 5125: 5116: 5097: 5091: 5080: 5069: 5042: 5032: 5004: 4997: 4972: 4968: 4958: 4947: 4919:– via 4913:. Retrieved 4907: 4903:Picard, Jean 4897: 4885:. Retrieved 4880: 4871: 4859:. Retrieved 4854: 4845: 4833:. Retrieved 4828: 4819: 4792: 4788: 4782: 4772:– via 4768:14 September 4766:. Retrieved 4759: 4731:, retrieved 4724:the original 4719: 4703: 4694: 4689: 4677:. Retrieved 4671: 4664: 4652:. Retrieved 4647: 4638: 4624: 4617: 4590: 4584: 4570: 4566:Picard, Jean 4560: 4533: 4527: 4513: 4489: 4479: 4472: 4427: 4421: 4394: 4391:Guedj, Denis 4370:. Retrieved 4366: 4357: 4345:. Retrieved 4341: 4331: 4320: 4294: 4288: 4279: 4275: 4262: 4245: 4241: 4231: 4214: 4189: 4183: 4139: 4118:. Retrieved 4114:the original 4110:www.bipm.org 4109: 4100: 4088:. Retrieved 4084:the original 4080:www.bipm.org 4079: 4070: 4045: 4032: 4015: 3994: 3984: 3842: 3824: 3816: 3808: 3798: 3790: 3780: 3770: 3760: 3741: 3727: 3681:, therefore 3477: 3451: 3435: 3406:Hebdomometre 3352:(11th CGPM) 3282: 3238:uncertainty 3233:uncertainty 3200: 3190: 3168: 3165:of a second. 3145: 3132: 3124: 3120: 3118: 3102: 3097: 3092:-stabilised 3087: 3071:triple point 3068: 3024: 3022: 3009:1 650 763.73 3006: 2998: 2993: 2975: 2955: 2951:nuclear spin 2942: 2934: 2899: 2869: 2789: 2779:to become a 2754: 2726: 2716: 2708: 2706: 2701: 2682: 2675:Henri Tresca 2660: 2656: 2646: 2635: 2629: 2623: 2560: 2544: 2536: 2520: 2516: 2491: 2468: 2455: 2442: 2411: 2383: 2332: 2324: 2306: 2296: 2272: 2252:and Colonel 2227: 2193:in 1815 and 2145:, while the 2135:independence 2120: 2048:represented 2024: 2008:Adriatic Sea 1964: 1881: 1861:Polar motion 1846: 1827: 1731: 1715:had founded 1713:Eratosthenes 1709:meridian arc 1701:South Africa 1680:Jean Brunner 1651:Muhammad Ali 1645: 1599: 1572: 1534:studied the 1529: 1518: 1503: 1323:Thomas Bugge 1296: 1233: 1218: 1194:yellow fever 1178:meridian arc 1175: 1170: 1154: 1140: 1070: 1047:meridian arc 1009: 998: 927: 890: 808: 626: 607:Earth radius 557: 549:Isaac Newton 513: 496: 461:] or 72 434: 401: 363: 295: 285:divided the 259: 232: 222: 189: 165: 134: 105: 96:, including 87: 65: 63: 29: 9284:(in French) 9231:(in French) 9204:: 242–263. 8981:16 December 8830:Article 3, 8450:: 445–469. 8270:: 244–245. 8203:(13): 193. 7780:(10): 914. 7476:: 147–162. 6741:(in German) 6456:(1): 6–21. 6397:(in French) 6081:E-Periodica 6046:www.bbc.com 5967:(in French) 5875:: 242–249. 5786:: 161–180. 5748:: 445–469. 5595:(1): 6–21. 5226:p. 10. 5204:4 September 5154:: 117–129. 4915:5 September 4887:5 September 4883:(in French) 4861:5 September 4835:5 September 4831:(in French) 4648:humanite.fr 4521:, 148, 154. 4090:13 November 4051: = 3.5 4008:6438.469 63 3955: / 3911: / 3870: / 3734:atomic time 3446:arcseconds. 3377:299,792,458 3162:299,792,458 3129:uncertainty 3116: THz. 2812:Jean Richer 2757:thermometry 2422:Koenigsberg 2215:cartography 2183:metrication 2032:joined the 1956:Switzerland 1940:Netherlands 1920:Mecklenburg 1641:Switzerland 1602:Fire Island 1375:Jean Darcet 1130:devised by 895:and in the 815:Switzerland 770:. In 1841, 744:arc of Peru 571:cartography 539:Jean Picard 515:Jean Richer 505:Jean Richer 415:Jean Picard 375:discovered 367:began with 260:The Nippur 252:, with the 9919:Categories 9229:Libération 7693:11 October 7387:12 October 7261:12 October 6164:13 October 6094:12 October 5831:15 October 5393:10 October 5024:1061216207 4543:2711753476 4372:15 October 4347:15 October 4063:References 3961: ( 3939:41°21′48″N 3917: ( 3895:44°25′57″N 3876: ( 3854:51°02′08″N 3358:0.01–0.005 3350:krypton-86 3249:10,000,000 3063:See also: 2990:krypton-86 2982:broadening 2896:wavelength 2870:The first 2697:m ± 0.2 μm 2399:gravimetry 2248:, General 2133:following 2121:After the 2058:Hervé Faye 2016:Baltic Sea 1779:Formentera 1604:the first 1552:centimetre 1548:CGS system 1359:Talleyrand 1019:See also: 939:Talleyrand 688:Gravimetry 637:flattening 617:Gravimeter 369:Copernicus 339:Paris feet 318:Roman mile 298:Roman foot 279:Roman foot 192:krypton-86 178:by thirty 114:flattening 46:North Pole 9678:118871648 9464:14 August 9344:Perot, A. 9288:7 October 9235:7 October 9171:1476-4687 8891:17 August 8818:0003-3804 8700:120943411 8692:1432-1394 8623:30 August 8339:121338356 8331:0031-9228 8284:0004-6302 8225:0004-6337 8138:29 August 8100:31 August 8073:29 August 7987:15 August 7904:cite book 7874:cite book 7810:125925505 7802:0949-7714 7755:125240402 7747:1521-3889 7657:198204435 7649:1432-1394 7554:27 August 7523:0398-7817 7492:0252-9211 7445:cite book 7414:cite book 7313:1 October 7288:1 October 7161:30 August 7136:119447198 7128:1432-1394 7106:CiteSeerX 7043:cite book 7013:cite book 6971:0004-6337 6949:(7): 97. 6918:CiteSeerX 6890:cite book 6858:cite book 6807:cite book 6799:861693071 6745:7 October 6719:7 October 6579:0096-3771 6514:cite book 6488:126724939 6480:1631-0705 6426:6 October 6401:6 October 6332:109333769 6271:cite book 6143:143514819 6135:0035-9149 5971:6 October 5940:cite book 5912:6 October 5889:0004-6302 5808:109333769 5800:0261-0523 5764:0261-0523 5687:0035-9149 5619:1631-0705 5518:31 August 5456:31 August 5333:0004-6337 5288:CiteSeerX 5263:30 August 5232:cite book 5160:0398-7817 5061:1298-9800 4981:0398-7817 4811:894499177 4609:894499177 4552:300706536 4454:cite book 4446:894499177 4413:758713673 4027: μm. 3989:compared. 3978:Barcelona 3942:2°10′01″E 3898:2°34′24″E 3857:2°22′34″E 3807:; 1 3789:; 1 3769:. 1 3703:π 3699:⋅ 3696:ℓ 3603:π 3569:ℓ 3504:ℓ 3498:π 3300:0.05–0.01 3110:microwave 3034:traceable 2932:in 1907. 2846:Euclidean 2773:metrology 2591:physicist 2497:in 1875, 2459:Neuchâtel 2441:(German: 2395:metrology 2321:expansion 2313:standards 2230:metrology 2177:work. In 2076:Argentina 2074:in 1888; 2036:in 1866. 2012:North Sea 1849:Barcelona 1624:in 1841. 1568:lightning 1530:In 1832, 1504:In 1816, 1284:Perpignan 1252:Lieusaint 1097:Condorcet 1065:Barcelona 1051:Barcelona 905:Greenwich 587:Leibniz's 283:Egyptians 271:Euphrates 88:With the 9805:19714162 9756:42447654 9748:19714161 9439:53495023 9346:(1907). 9327:(3): 85. 8972:archived 8951:(2006), 8176:15 March 8171:usma.org 8017:16069502 7723:(5): 2. 7531:43861533 6691:36747385 6659:27274915 5431:36747385 5168:43861533 4989:43861533 4905:(1671). 4757:(1821). 4711:(2018), 4679:2 August 4654:3 August 4568:(1671). 4393:(2011). 4010: Å. 4004:ångström 3974:Montjuïc 3400:See also 3293:standard 3258:Delambre 3254:meridian 3236:Relative 3231:Absolute 3208:realised 3123: = 3075:nitrogen 2946:isotopes 2926:< 0.1 2904:ångström 2836:, while 2663:platinum 2553:and 10% 2551:platinum 2219:railways 2175:cadastre 2173:for the 2030:Portugal 2014:and the 1988:Milejewo 1877:latitude 1832:— 1819:Montjuïc 1795:spheroid 1783:Shetland 1769:and the 1703:through 1664:cadastre 1606:baseline 1597:(CIPM). 1544:kilogram 1292:Pyrenees 1272:used by 1180:fell to 1118:Shetland 1085:Lagrange 663:spheroid 581:, which 417:through 393:pendulum 381:pendulum 287:Sumerian 153:Americas 56:through 54:meridian 9785:Bibcode 9728:Bibcode 9704:. 1975. 9658:Bibcode 9633:1841238 9613:Bibcode 9576:Bibcode 9547:4224209 9527:Bibcode 9490:Bibcode 9419:Bibcode 9381:Bibcode 9179:4140694 9149:Bibcode 9005:Bibcode 8920:Bibcode 8796:Bibcode 8672:Bibcode 8477:Gallica 8311:Bibcode 8272:Bibcode 8205:Bibcode 8094:Gallica 7782:Bibcode 7725:Bibcode 7629:Bibcode 7155:Gallica 7098:Bibcode 6951:Bibcode 6650:4654608 6567:Bibcode 6458:Bibcode 6351:Gallica 6318:: 174. 6192:5 April 5992:Gallica 5877:Bibcode 5597:Bibcode 5512:Gallica 5450:Gallica 5399:Gallica 5257:Gallica 5195:Bibcode 5193:: 290. 5131:10 June 4921:Gallica 4774:Gallica 4733:20 June 4576:Gallica 4194:Bibcode 4120:17 June 3375:⁄ 3322:0.2–0.1 3269:0.5–0.1 3262:Méchain 3247:⁄ 3160:⁄ 3090:methane 3052:at the 2966:mercury 2962:krypton 2958:cadmium 2919:⁄ 2892:cadmium 2816:Cayenne 2785:physics 2777:geodesy 2733:bending 2667:iridium 2555:iridium 2535:(CGPM: 2403:geodesy 2344:and in 2342:Prussia 2234:geodesy 2044:, that 1980:Denmark 1972:Palermo 1904:Denmark 1888:Prussia 1785:to the 1775:Dunkirk 1717:geodesy 1633:Aarberg 1593:at the 1514:Germany 1461:⁠ 1449:⁠ 1274:Cassini 1227:to the 1164:⁄ 1151:degrees 1089:Laplace 1041:of the 1005:Discuss 930:geodesy 855:⁠ 843:⁠ 827:Genevan 792:⁠ 780:⁠ 764:⁠ 752:⁠ 740:⁠ 728:⁠ 724:⁠ 712:⁠ 704:⁠ 692:⁠ 684:⁠ 672:⁠ 659:gravity 655:theorem 639:of the 603:Lapland 599:Ecuador 575:geodesy 523:Cayenne 509:Cayenne 373:Galileo 310:fingers 291:fingers 130:⁠ 118:⁠ 50:Equator 48:to the 9875: 9823:, 1983 9803: 9754: 9746: 9676: 9631: 9545: 9518:Nature 9437: 9260: 9177: 9169: 9141:Nature 9121:15 May 8964: 8859:21 May 8816: 8698: 8690: 8483:15 May 8423:26 May 8395:26 May 8370:22 May 8337: 8329: 8282: 8223: 8127:: 33. 8015: 7958: 7931: 7808: 7800: 7753: 7745: 7682:: 33. 7655: 7647: 7598: 7529: 7521: 7511:Thalès 7490: 7199: 7134: 7126: 7108: 6969: 6920: 6797: 6787: 6689: 6679: 6657: 6647: 6577: 6486: 6478: 6357:13 May 6330: 6243: 6218: 6141: 6133: 6051:21 May 6023: 5998:13 May 5887: 5806: 5798: 5762: 5685: 5642: 5617: 5429: 5419: 5354:: 5331: 5290: 5166: 5158: 5148:Thalès 5104: 5059: 5022: 5012: 4987: 4979: 4969:Thalès 4809: 4799: 4697:, 1675 4607: 4597: 4550: 4540: 4444: 4434: 4411: 4401: 4317: 4282:: 265. 4280:XXXVII 3834:toises 3827:lignes 3819:lignes 3802:pouces 3748:lignes 3664: 3632:Being 3388: 3360: 3324: 3302: 3271: 3191:ν 3177:to be 3149:iodine 3015:and 5d 2804:Newton 2632:Sèvres 2529:Sèvres 2481:, and 2418:Altona 2380:(1829) 2346:France 2317:alloys 2254:Ibáñez 2250:Baeyer 2139:Brazil 2068:Mexico 2054:Vienna 2050:France 1992:Poland 1958:. The 1948:Poland 1857:zenith 1807:Geneva 1787:Sahara 1655:Boulaq 1591:Russia 1540:second 1500:, 1817 1279:toises 1259:toises 1237:toises 1200:lignes 1156:grades 1039:belfry 1027:, and 869:later 794:. His 789:299.15 544:toises 477:lignes 471:inches 465:pouces 439:lignes 397:second 371:work. 331:points 322:league 308:or 16 306:inches 267:Nippur 223:ν 209:to be 9925:Metre 9752:S2CID 9674:S2CID 9629:S2CID 9543:S2CID 9435:S2CID 9405:(PDF) 9175:S2CID 9037:(PDF) 8975:(PDF) 8958:(PDF) 8794:(5). 8769:Dodis 8696:S2CID 8561:(PDF) 8502:[ 8360:(PDF) 8335:S2CID 7832:(PDF) 7806:S2CID 7751:S2CID 7653:S2CID 7527:JSTOR 7132:S2CID 7066:(PDF) 6484:S2CID 6328:S2CID 6139:S2CID 5804:S2CID 5567:(PDF) 5476:(PDF) 5363:(PDF) 5164:JSTOR 4985:JSTOR 4791:[ 4727:(PDF) 4716:(PDF) 4272:(PDF) 4223:(PDF) 4180:(PDF) 3811:pouce 3784:pieds 3774:toise 3441:8.794 3427:Notes 3383:1983 3355:1960 3337:1927 3319:1889 3297:1799 3266:1798 3228:Date 3083:phase 3079:laser 2888:Perot 2884:Fabry 2842:space 2761:invar 2692:0.999 2072:Japan 2064:Chile 2026:Spain 1967:geoid 1946:(for 1791:geoid 1705:Egypt 1693:Borda 1659:Cairo 1635:, in 1414:1798. 1265:toise 1244:Melun 1225:Rodez 1190:Arago 1171:grade 1093:Monge 1081:Borda 995:split 901:Paris 852:298.3 483:lines 481:[ 469:[ 457:[ 453:pieds 445:toise 391:" (a 335:toise 329:of 6 327:lines 304:, 12 302:palms 262:cubit 106:metre 58:Paris 38:metre 9873:ISBN 9801:PMID 9744:PMID 9466:2010 9290:2023 9258:ISBN 9237:2023 9167:ISSN 9123:2019 8983:2021 8962:ISBN 8893:2010 8861:2020 8814:ISSN 8688:ISSN 8649:2018 8625:2016 8590:2021 8485:2019 8425:2017 8397:2017 8372:2017 8327:ISSN 8280:ISSN 8221:ISSN 8178:2021 8140:2023 8102:2023 8075:2023 8013:OCLC 7989:2010 7956:ISBN 7929:ISBN 7910:link 7880:link 7798:ISSN 7743:ISSN 7695:2023 7645:ISSN 7596:ISBN 7556:2023 7519:ISSN 7488:ISSN 7451:link 7420:link 7389:2021 7315:2023 7290:2023 7263:2021 7197:ISBN 7163:2021 7124:ISSN 7049:link 7019:link 6967:ISSN 6896:link 6881:1836 6864:link 6813:link 6795:OCLC 6785:ISBN 6747:2023 6721:2023 6687:OCLC 6677:ISBN 6655:PMID 6575:ISSN 6520:link 6476:ISSN 6428:2023 6403:2023 6359:2019 6277:link 6241:ISBN 6216:ISBN 6194:2011 6166:2015 6131:ISSN 6096:2021 6053:2019 6021:ISBN 6000:2019 5973:2023 5946:link 5914:2023 5885:ISSN 5833:2023 5796:ISSN 5760:ISSN 5723:help 5683:ISSN 5640:ISBN 5615:ISSN 5520:2023 5458:2023 5427:OCLC 5417:ISBN 5395:2018 5329:ISSN 5265:2021 5238:link 5206:2018 5156:ISSN 5133:2020 5102:ISBN 5057:ISSN 5020:OCLC 5010:ISBN 4977:ISSN 4917:2018 4889:2018 4863:2018 4837:2018 4807:OCLC 4797:ISBN 4770:2018 4735:2019 4681:2021 4656:2021 4605:OCLC 4595:ISBN 4548:OCLC 4538:ISBN 4464:link 4460:link 4442:OCLC 4432:ISBN 4409:OCLC 4399:ISBN 4374:2023 4349:2023 4145:BIPM 4122:2019 4092:2019 3793:pied 3343:n/a 3340:n/a 3314:CGPM 3260:and 3137:CGPM 3001:CGPM 2964:and 2912:CIPM 2886:and 2878:and 2834:mass 2832:and 2830:time 2694:9984 2589:and 2561:The 2511:The 2426:yard 2420:and 2232:and 2141:and 2108:and 2078:and 2070:and 2028:and 2006:and 1996:Alps 1984:Bonn 1974:and 1687:and 1562:and 1556:gram 1305:and 1248:and 1184:and 1111:and 1095:and 1037:The 969:yard 964:yard 944:foot 919:yard 903:and 873:and 601:and 517:and 459:foot 343:yard 314:pace 296:The 235:yard 166:The 147:and 64:The 9793:doi 9736:doi 9666:doi 9621:doi 9584:doi 9535:doi 9523:187 9498:doi 9427:doi 9358:144 9206:doi 9157:doi 9145:134 9013:doi 8928:doi 8804:doi 8792:531 8680:doi 8452:doi 8448:163 8319:doi 8213:doi 8129:doi 7790:doi 7733:doi 7721:531 7684:doi 7637:doi 7588:doi 7584:143 7478:doi 7474:178 7252:doi 7116:doi 6959:doi 6645:PMC 6637:doi 6633:111 6602:doi 6466:doi 6320:doi 6316:157 6123:doi 6085:doi 5788:doi 5784:157 5750:doi 5746:163 5673:doi 5605:doi 5540:doi 5321:doi 5047:doi 4250:doi 4202:doi 4055:10. 3469:700 3466:870 3463:597 3461:149 3443:143 3393:10 3390:nm 3386:0.1 3365:10 3362:μm 3329:10 3326:μm 3307:10 3304:mm 3276:10 3273:mm 3184:458 3181:792 3179:299 3133:two 3073:of 3056:at 3025:not 2953:). 2137:of 1990:in 1950:), 1934:), 1777:to 1471:740 1468:130 1458:334 1385:, 1325:, 1313:: 1262:(a 1166:100 1159:" ( 1063:in 1003:. ( 817:by 761:300 737:334 721:305 701:359 681:279 525:in 429:at 421:of 399:). 216:458 213:792 211:299 127:334 116:of 9921:: 9904:. 9868:. 9843:. 9829:^ 9799:. 9791:. 9779:. 9750:. 9742:. 9734:. 9722:. 9700:. 9672:. 9664:. 9654:20 9652:. 9627:. 9619:. 9609:22 9607:. 9582:. 9572:29 9570:. 9555:^ 9541:. 9533:. 9521:. 9496:. 9484:. 9457:, 9433:. 9425:. 9415:38 9413:. 9407:. 9392:^ 9350:. 9342:; 9325:11 9304:p. 9280:. 9227:. 9200:. 9196:. 9173:. 9165:. 9155:. 9143:. 9139:. 9109:. 9057:. 9053:. 9011:. 9001:34 8999:. 8970:, 8940:^ 8926:. 8914:. 8900:^ 8879:, 8851:. 8839:^ 8812:. 8802:. 8790:. 8786:. 8767:. 8741:^ 8694:. 8686:. 8678:. 8668:78 8666:. 8640:. 8616:, 8597:^ 8563:. 8537:^ 8525:. 8512:^ 8475:. 8446:. 8442:. 8416:. 8405:^ 8388:. 8362:. 8347:^ 8333:. 8325:. 8317:. 8307:62 8305:. 8301:. 8278:. 8268:30 8266:. 8262:. 8250:^ 8219:. 8211:. 8201:17 8199:. 8195:. 8169:. 8125:21 8119:. 8092:. 8061:. 7997:^ 7970:^ 7906:}} 7902:{{ 7876:}} 7872:{{ 7818:^ 7804:. 7796:. 7788:. 7778:90 7776:. 7772:. 7749:. 7741:. 7731:. 7719:. 7715:. 7703:^ 7680:21 7674:. 7651:. 7643:. 7635:. 7625:54 7619:. 7594:. 7578:. 7564:^ 7547:. 7525:. 7513:. 7509:. 7486:. 7472:. 7468:. 7447:}} 7443:{{ 7416:}} 7412:{{ 7357:^ 7306:. 7280:, 7248:89 7242:. 7228:^ 7211:^ 7153:. 7130:. 7122:. 7114:. 7104:. 7094:71 7092:. 7088:. 7074:^ 7045:}} 7041:{{ 7015:}} 7011:{{ 6965:. 6957:. 6947:19 6945:. 6941:. 6904:^ 6892:}} 6888:{{ 6860:}} 6856:{{ 6838:^ 6809:}} 6805:{{ 6793:. 6767:^ 6737:. 6707:. 6685:. 6653:. 6643:. 6631:. 6627:. 6615:^ 6587:^ 6573:. 6563:13 6561:. 6557:. 6545:^ 6516:}} 6512:{{ 6482:. 6474:. 6464:. 6454:20 6448:. 6436:^ 6419:. 6393:. 6349:. 6326:. 6314:. 6310:. 6294:^ 6273:}} 6269:{{ 6202:^ 6137:. 6129:. 6119:62 6117:. 6113:. 6079:. 6044:. 5990:. 5963:. 5942:}} 5938:{{ 5905:. 5883:. 5873:30 5871:. 5867:. 5824:. 5802:. 5794:. 5782:. 5758:. 5744:. 5740:. 5714:: 5712:}} 5708:{{ 5681:. 5669:62 5667:. 5663:. 5613:. 5603:. 5593:20 5587:. 5575:^ 5553:^ 5510:. 5478:. 5448:. 5425:. 5387:90 5385:. 5379:. 5327:. 5317:19 5315:. 5311:. 5282:. 5255:. 5234:}} 5230:{{ 5162:. 5150:. 5124:. 5079:. 5055:. 5041:. 5018:. 4983:. 4971:. 4967:. 4946:. 4929:^ 4853:. 4805:. 4753:; 4742:^ 4718:, 4646:. 4630:20 4603:. 4546:. 4501:^ 4456:}} 4452:{{ 4440:. 4407:. 4382:^ 4365:. 4340:. 4303:^ 4278:. 4274:. 4246:13 4244:. 4240:. 4200:. 4190:19 4188:. 4182:. 4153:^ 4143:, 4130:^ 4108:. 4078:. 3976:, 3972:– 3928:– 3316:) 3194:Cs 3143:. 3125:fλ 3048:A 3013:10 2960:, 2921:10 2822:. 2818:, 2787:. 2627:. 2617:, 2593:, 2477:, 2466:. 2372:. 2181:, 2125:, 2066:, 1942:, 1938:, 1930:, 1926:, 1922:, 1918:, 1914:, 1910:, 1902:, 1898:, 1719:. 1639:, 1554:, 1434:, 1430:, 1397:. 1389:, 1381:, 1377:, 1373:, 1369:, 1365:, 1353:: 1337:, 1333:: 1321:: 1317:, 1309:, 1301:: 1107:. 1091:, 1087:, 1083:, 1023:, 1007:) 925:. 877:. 821:, 806:. 706:. 686:. 573:, 547:. 226:Cs 163:. 132:. 9881:. 9807:. 9795:: 9787:: 9781:8 9771:2 9758:. 9738:: 9730:: 9724:8 9680:. 9668:: 9660:: 9635:. 9623:: 9615:: 9590:. 9586:: 9578:: 9549:. 9537:: 9529:: 9504:. 9500:: 9492:: 9486:2 9441:. 9429:: 9421:: 9383:: 9377:2 9292:. 9266:. 9239:. 9212:. 9208:: 9202:5 9181:. 9159:: 9151:: 9125:. 9019:. 9015:: 9007:: 8934:. 8930:: 8922:: 8916:3 8863:. 8834:. 8820:. 8806:: 8798:: 8702:. 8682:: 8674:: 8651:. 8487:. 8460:. 8454:: 8427:. 8399:. 8374:. 8341:. 8321:: 8313:: 8286:. 8274:: 8244:. 8227:. 8215:: 8207:: 8180:. 8142:. 8131:: 8104:. 8077:. 8019:. 7991:. 7964:. 7937:. 7912:) 7882:) 7812:. 7792:: 7784:: 7757:. 7735:: 7727:: 7697:. 7686:: 7659:. 7639:: 7631:: 7604:. 7590:: 7558:. 7533:. 7515:2 7494:. 7480:: 7453:) 7422:) 7391:. 7317:. 7265:. 7254:: 7222:. 7205:. 7165:. 7138:. 7118:: 7100:: 7051:) 7021:) 6973:. 6961:: 6953:: 6926:. 6898:) 6884:. 6866:) 6815:) 6801:. 6749:. 6723:. 6693:. 6639:: 6604:: 6581:. 6569:: 6522:) 6490:. 6468:: 6460:: 6430:. 6405:. 6361:. 6334:. 6322:: 6279:) 6249:. 6224:. 6196:. 6168:. 6145:. 6125:: 6098:. 6087:: 6055:. 6029:. 6002:. 5975:. 5948:) 5916:. 5891:. 5879:: 5835:. 5810:. 5790:: 5766:. 5752:: 5725:) 5721:( 5689:. 5675:: 5648:. 5621:. 5607:: 5599:: 5542:: 5522:. 5460:. 5433:. 5401:. 5335:. 5323:: 5296:. 5267:. 5240:) 5197:: 5191:3 5170:. 5152:2 5135:. 5110:. 5063:. 5049:: 5026:. 4991:. 4973:2 4923:. 4891:. 4865:. 4839:. 4813:. 4776:. 4683:. 4658:. 4632:. 4611:. 4578:. 4554:. 4519:7 4466:) 4448:. 4415:. 4376:. 4351:. 4256:. 4252:: 4208:. 4204:: 4196:: 4124:. 4094:. 4053:× 4049:r 4046:u 3965:) 3921:) 3880:) 3837:. 3736:. 3722:. 3707:2 3692:= 3689:g 3668:s 3661:1 3658:= 3653:2 3649:/ 3645:1 3641:T 3618:. 3613:2 3608:) 3598:2 3594:/ 3590:1 3586:T 3580:( 3575:g 3572:= 3546:2 3542:/ 3538:1 3534:T 3513:. 3507:g 3495:2 3492:= 3489:T 3481:: 3373:1 3245:1 3197:. 3189:Δ 3175:c 3158:1 3121:c 3098:λ 3096:( 3017:5 2994:λ 2992:( 2917:1 2900:λ 2743:. 2648:" 2515:( 2283:. 2112:. 1978:( 1825:. 1742:. 1732:a 1550:( 1488:. 1466:5 1455:/ 1452:1 1423:. 1162:1 849:/ 846:1 786:/ 783:1 758:/ 755:1 734:/ 731:1 718:/ 715:1 698:/ 695:1 678:/ 675:1 623:. 229:. 221:Δ 207:c 124:/ 121:1 60:. 20:)

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.

Knowledge

History of the metre

Index