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History of the metre

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A league is a unit of length . It was common in Europe and Latin America , but is no longer an official unit in any nation. Derived from an ancient Celtic unit and adopted by the Romans as the leuga , the league became a common unit of measurement throughout western Europe. Since the Middle Ages, many values have been specified in several countries, ranging from 2.2 km (1.4 mi) to 7.9 km (4.9 mi).

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155-473: The history of the metre starts with the Scientific Revolution that is considered to have begun with Nicolaus Copernicus 's publication of De revolutionibus orbium coelestium 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

310-622: A Central Office, located at the Prussian Geodetic Institute, whose management was entrusted to Johann Jacob Baeyer. 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 geoid 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

465-593: A Technical Commission was set up to continue, by adopting the procedures instituted in Europe, the cadastre work inaugurated under Muhammad Ali. This Commission suggested to Viceroy Mohammed Sa'id Pasha the idea of buying geodetic devices which were ordered in France. While Mahmud Ahmad Hamdi al-Falaki was in charge, in Egypt, of the direction of the work of the general map, the viceroy entrusted to Ismail Mustafa al-Falaki

620-482: A determination of the size of the Earth, then considered as a sphere, by Jean Picard through triangulation of Paris meridian . In 1671, Jean Picard also measured the length of a seconds pendulum at Paris Observatory and proposed this unit of measurement to be called the astronomical radius (French: Rayon Astronomique ). He found the value of 440.5 lignes of the Toise of Châtelet (a toise [English: fathom ]

775-575: 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. It was well known that by measuring the latitude of two stations in Barcelona , 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

930-479: A direct tie between "particular aspects of traditional Christianity" and the rise of science. The " Aristotelian tradition " was still an important intellectual framework in the 17th century, although by that time natural philosophers had moved away from much of it. Key scientific ideas dating back to classical antiquity had changed drastically over the years and in many cases had been discredited. The ideas that remained, which were transformed fundamentally during

1085-405: A distance is permitted, particles or corpuscles of matter are fundamentally inert. Motion is caused by direct physical collision. Where natural substances had previously been understood organically, the mechanical philosophers viewed them as machines. As a result, Newton's theory seemed like some kind of throwback to "spooky action at a distance ". According to Thomas Kuhn, Newton and Descartes held

1240-522: A distance of 571 mm from each other. These support locations are at the Bessel points 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 bending 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. The comparison of

1395-464: A few years from its first promulgation." In the 19th century, William Whewell described the revolution in science itself – the scientific method – that had taken place in the 15th–16th century. "Among the most conspicuous of the revolutions which opinions on this subject have undergone, is the transition from an implicit trust in the internal powers of man's mind to a professed dependence upon external observation; and from an unbounded reverence for

1550-418: A flattening of ⁠ 1 / 359 ⁠ . Adrien-Marie Legendre meanwhile found at the same time a flattening of ⁠ 1 / 305 ⁠ . The Weights and Measures Commission would adopt in 1799 a flattening of ⁠ 1 / 334 ⁠ by combining the arc of Peru 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

1705-412: A fundamental transformation in scientific ideas across mathematics, physics, astronomy, and biology in institutions supporting scientific investigation and in the more widely held picture of the universe. The Scientific Revolution led to the establishment of several modern sciences. In 1984, Joseph Ben-David wrote: Rapid accumulation of knowledge, which has characterized the development of science since

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1860-417: A great advancement in science and a progeny of inventions that would relieve mankind's miseries and needs. His Novum Organum was published in 1620, in which he argues man is "the minister and interpreter of nature," "knowledge and human power are synonymous," "effects are produced by the means of instruments and helps," "man while operating can only apply or withdraw natural bodies; nature internally performs

2015-530: A league was also a unit of area, defined as 25 million square varas or about 4,428.4 acres . This usage of league is referenced frequently in the Texas Constitution . So defined, a league of land would encompass a square that is one Spanish league on each side. A comparison of the different lengths for a "league", in different countries and at different times in history, is given in the table below. Miles are also included in this list because of

2170-461: A mechanical, mathematical world to be known through experimental research. Though it is certainly not true that Newtonian science was like modern science in all respects, it conceptually resembled ours in many ways. Many of the hallmarks of modern science, especially with regard to its institutionalization and professionalization, did not become standard until the mid-19th century. The Aristotelian scientific tradition's primary mode of interacting with

2325-915: A metre "too short" compared to a more general definition taken from the average of a large number of arcs. As early as 1861, Johann Jacob Baeyer sent a memorandum to the King of Prussia recommending international collaboration in Central Europe with the aim of determining the shape and dimensions of the Earth. At the time of its creation, the association had sixteen member countries: Austrian Empire , Kingdom of Belgium , Denmark , seven German states ( Grand Duchy of Baden , Kingdom of Bavaria , Kingdom of Hanover , Mecklenburg , Kingdom of Prussia , Kingdom of Saxony , Saxe-Coburg and Gotha ), Kingdom of Italy , Netherlands , Russian Empire (for Poland ), United Kingdoms of Sweden and Norway , as well as Switzerland . The Central European Arc Measurement created

2480-472: A much-improved precision in the measurement of angles between landmarks, but insisted that two different version of the device be calibrated one in degrees and another in " grades " ( 1 ⁄ 100 of a quarter-circle), with 100 minutes to a grade and 100 seconds to a minute. The task of surveying the meridian arc fell to Pierre Méchain and Jean-Baptiste Delambre , and took more than six years (1792–1798). The technical difficulties were not

2635-411: A new era of geodesy . 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 gravitational acceleration by means of pendulum. In 1866, the most important concern was that the Toise of Peru, the standard of

2790-568: 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 Ferdinand Rudolph Hassler '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

2945-482: A projectile's trajectory from a parabola would be only very slight. Scientific knowledge, according to the Aristotelians, was concerned with establishing true and necessary causes of things. To the extent that medieval natural philosophers used mathematical problems, they limited social studies to theoretical analyses of local speed and other aspects of life. The actual measurement of a physical quantity, and

3100-438: A reliable foundation on which to confirm mathematical laws using inductive reasoning. Galileo showed an appreciation for the relationship between mathematics, theoretical physics, and experimental physics. He understood the parabola , both in terms of conic sections and in terms of the ordinate (y) varying as the square of the abscissa (x). Galilei further asserted that the parabola was the theoretically ideal trajectory of

3255-611: A scientific methodology in which empiricism played a large role. By the start of the Scientific Revolution, empiricism had already become an important component of science and natural philosophy. Prior thinkers , including the early-14th-century nominalist philosopher William of Ockham , had begun the intellectual movement toward empiricism. The term British empiricism came into use to describe philosophical differences perceived between two of its founders Francis Bacon , described as empiricist, and René Descartes , who

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3410-558: A scientific revolution emerge in the 18th-century work of Jean Sylvain Bailly , who described a two-stage process of sweeping away the old and establishing the new. There continues to be scholarly engagement regarding the boundaries of the Scientific Revolution and its chronology. Great advances in science have been termed "revolutions" since the 18th century. For example, in 1747, the French mathematician Alexis Clairaut wrote that " Newton

3565-414: A straight road between Melun and Lieusaint . In an operation taking six weeks, the baseline was accurately measured using four platinum rods, each of length two toises (a toise being about 1.949 m). Thereafter he used, where possible, the triangulation points used by Cassini in his 1744 survey of France. Méchain's baseline, of a similar length (6,006.25 toises ), and also on

3720-1274: A straight section of road between Vernet (in the Perpignan area) and Salces (now Salses-le-Chateau ). Although Méchain's sector was half the length of Delambre, it included the Pyrenees and hitherto unsurveyed parts of Spain. 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 Batavian Republic : Henricus Aeneae and Jean Henri van Swinden , Cisalpine Republic : Lorenzo Mascheroni , Kingdom of Denmark : Thomas Bugge , Kingdom of Spain : Gabriel Císcar and Agustín de Pedrayes, Helvetic Republic : Johann Georg Tralles , Ligurian Republic : Ambrogio Multedo, Kingdom of Sardinia : Prospero Balbo, Antonio Vassali Eandi, Roman Republic : Pietro Franchini, Tuscan Republic : Giovanni Fabbroni who had been invited by Talleyrand . The French commission comprised Jean-Charles de Borda , Barnabé Brisson , Charles-Augustin de Coulomb , Jean Darcet , René Just Haüy , Joseph-Louis Lagrange , Pierre- Simon Laplace , Louis Lefèvre-Ginneau , Pierre Méchain and Gaspar de Prony . In 1816, Ferdinand Rudolph Hassler

3875-401: A uniformly accelerated projectile in the absence of friction and other disturbances. He conceded that there are limits to the validity of this theory, noting on theoretical grounds that a projectile trajectory of a size comparable to that of the Earth could not possibly be a parabola, but he nevertheless maintained that for distances up to the range of the artillery of his day, the deviation of

4030-538: A value of ⁠ 1 / 299.15 ⁠ . His reference ellipsoid would long be used by geodesists. An even more accurate value was proposed in 1901 by Friedrich Robert Helmert according to gravity measurements performed under the auspices of the International Geodetic Association . Significant improvements in gravity measuring instruments must also be attributed to Bessel. He devised a gravimeter constructed by Adolf Repsold which

4185-441: Is 5.572 km (3.462 mi) or 6,666 varas : 1 vara is 0.83 m (33 in). On land, the league is most commonly defined as three miles (4.83 km), although the length of a mile could vary from place to place as well as depending on the era. At sea, a league is three  nmi (3.452 mi; 5.556 km). English usage also included many of the other leagues mentioned below (for example, in discussing

4340-459: Is called accident, if sought for, experiment. The true method of experience first lights the candle [hypothesis], and then by means of the candle shows the way [arranges and delimits the experiment]; commencing as it does with experience duly ordered and digested, not bungling or erratic, and from it deducing axioms [theories], and from established axioms again new experiments. Gilbert was an early advocate of this method. He passionately rejected both

4495-412: Is defined as 6 pieds [ foot ] or 72 pouces [ inches ] or 864 lignes [ lines ]), which had been recently renewed. He proposed a universal toise (French: toise universelle ) which was twice the length of the seconds pendulum. In 1675, Tito Livio Burattini suggested the term metro cattolico meaning universal measure for this unit of length, but then it

4650-531: Is not the same as a retrogression) to a scholastic standard. Innate attractions and repulsions joined size, shape, position and motion as physically irreducible primary properties of matter. Newton had also specifically attributed the inherent power of inertia to matter, against the mechanist thesis that matter has no inherent powers. But whereas Newton vehemently denied gravity was an inherent power of matter, his collaborator Roger Cotes made gravity also an inherent power of matter, as set out in his famous preface to

4805-565: Is quite put out; The Sun is lost, and th'earth, and no man's wit Can well direct him where to look for it. Butterfield was less disconcerted but nevertheless saw the change as fundamental: Since that revolution turned the authority in English not only of the Middle Ages but of the ancient world—since it started not only in the eclipse of scholastic philosophy but in the destruction of Aristotelian physics—it outshines everything since

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4960-421: Is the "final cause". The final cause was the aim, goal, or purpose of some natural process or man-made thing. Until the Scientific Revolution, it was very natural to see such aims, such as a child's growth, for example, leading to a mature adult. Intelligence was assumed only in the purpose of man-made artifacts; it was not attributed to other animals or to nature. In " mechanical philosophy " no field or action at

5115-527: Is this unit that is referenced in both the title and the body text of Jules Verne 's novel Twenty Thousand Leagues Under the Seas (1870). In some rural parts of Mexico, the league (Spanish legua ) is still used in the original sense of the distance that can be covered on foot in an hour, so that a league along a good road on level ground is a greater distance than a league on a difficult path over rough terrain. In Portugal , Brazil and other parts of

5270-570: Is traditionally assumed to start with the Copernican Revolution (initiated in 1543) and to be complete in the "grand synthesis" of Isaac Newton's 1687 Principia . Much of the change of attitude came from Francis Bacon whose "confident and emphatic announcement" in the modern progress of science inspired the creation of scientific societies such as the Royal Society , and Galileo who championed Copernicus and developed

5425-636: The mètre des Archives. In 1867, the General Conference of the European Arc Measurement (German: Europäische Gradmessung ) called for the creation of a new, international prototype metre (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

5580-550: The Baconian method , or simply the scientific method. His demand for a planned procedure of investigating all things natural marked a new turn in the rhetorical and theoretical framework for science, much of which still surrounds conceptions of proper methodology today. Bacon proposed a great reformation of all process of knowledge for the advancement of learning divine and human, which he called Instauratio Magna (The Great Instauration). For Bacon, this reformation would lead to

5735-551: The Anglo-French Survey , thus the French meridian arc, which would extend northwards across the United Kingdom, would also extend southwards to Barcelona, later to Balearic Islands . Jean-Baptiste Biot and François Arago 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

5890-600: The Anglo-French Survey , which aimed to connect Paris and Greenwich Observatories and led to the Principal Triangulation of Great Britain . The unit of length used by the French was the Toise de Paris , while the English one was the yard , which became the geodetic unit used in the British Empire . Despite scientific progresses in the field of geodesy , little practical advance was made towards

6045-469: The British Crown . The idea of the seconds pendulum as a length standard did not die completely, and such a definition was used to define the yard 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 yard standard

6200-657: The International Committee for Weights and Measures (CIPM). In 1834, Hassler, measured at Fire Island the first baseline of the Survey of the Coast, shortly before Louis Puissant declared to the French Academy of Sciences in 1836 that Jean Baptiste Joseph Delambre and Pierre Méchain had made errors in the meridian arc measurement , which had been used to determine the length of the metre. Errors in

6355-610: The Neolithic Revolution . The era of the Scientific Renaissance focused to some degree on recovering the knowledge of the ancients and is considered to have culminated in Isaac Newton 's 1687 publication Principia which formulated the laws of motion and universal gravitation , thereby completing the synthesis of a new cosmology . The subsequent Age of Enlightenment saw the concept of

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6510-651: The North Sea and the Baltic Sea in the north. In his mind, the cooperation of all the States of Central Europe could open the field to scientific research of the highest interest, research that each State, taken in isolation, was not able to undertake. Spain and Portugal joined the European Arc Measurement in 1866. French Empire hesitated for a long time before giving in to the demands of

6665-532: The Novum Organum of Bacon, in which the inductive method of philosophizing was first explained." Galileo Galilei has been called the "father of modern observational astronomy ," the "father of modern physics," the "father of science," and "the Father of Modern Science." His original contributions to the science of motion were made through an innovative combination of experiment and mathematics. Galileo

6820-481: The Principia's 1713 second edition which he edited, and contradicted Newton. And it was Cotes's interpretation of gravity rather than Newton's that came to be accepted. The first moves towards the institutionalization of scientific investigation and dissemination took the form of the establishment of societies, where new discoveries were aired, discussed, and published. The first scientific society to be established

6975-501: The Treaty of Tordesillas ). The French lieue  — at different times — existed in several variants, namely 10,000, 12,000, 13,200 and 14,400 French feet , about 3.25 to 4.68 km (2.02 to 2.91 miles). It was used along with the metric system for a while, but is long discontinued. A metric lieue was used in France from 1812 to 1840, with 1 metric lieue being exactly 4,000 m, or 4 km (about 2.5 mi). It

7130-466: The heliocentric system . In the Axioms Scholium of his Principia, Newton said its axiomatic three laws of motion were already accepted by mathematicians such as Christiaan Huygens , Wallace, Wren and others. While preparing a revised edition of his Principia , Newton attributed his law of gravity and his first law of motion to a range of historical figures. Despite these qualifications,

7285-559: The second to the basic units of the metre and the kilogram in the form of the CGS system ( centimetre , gram , second). In 1836, he founded the Magnetischer Verein, the first international scientific association, in collaboration with Alexander von Humboldt and Wilhelm Edouard Weber . The coordination of the observation of geophysical phenomena such as the Earth's magnetic field, lightning and gravity in different points of

7440-450: The solar parallax 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 radius of Earth , which had been measured by their colleague Jean Picard in 1669 as 3,269,000 toises . Isaac Newton used this measurement for establishing his law of universal gravitation . Picard's geodetic observations had been confined to

7595-401: The teleological principle that God conserved the amount of motion in the universe: Gravity, interpreted as an innate attraction between every pair of particles of matter, was an occult quality in the same sense as the scholastics' "tendency to fall" had been.... By the mid eighteenth century that interpretation had been almost universally accepted, and the result was a genuine reversion (which

7750-522: The 17th century, had never occurred before that time. The new kind of scientific activity emerged only in a few countries of Western Europe, and it was restricted to that small area for about two hundred years. (Since the 19th century, scientific knowledge has been assimilated by the rest of the world). Many contemporary writers and modern historians claim that there was a revolutionary change in world view. In 1611 English poet John Donne wrote: [The] new Philosophy calls all in doubt, The Element of fire

7905-556: The 18th century, in addition to its significance for cartography , geodesy grew in importance as a means of empirically demonstrating the theory of gravity , which Émilie du Châtelet promoted in France in combination with Leibniz's mathematical work and because the radius of the Earth was the unit to which all celestial distances were to be referred. Indeed, Earth proved to be an oblate spheroid through geodetic surveys in Ecuador and Lapland and this new data called into question

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8060-399: The 19th century, the creation of the International Geodetic Association 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 electrical telegraph . Furthermore, advances in metrology combined with those of gravimetry have led to

8215-483: The 20th century, Alexandre Koyré introduced the term "scientific revolution", centering his analysis on Galileo. The term was popularized by Herbert Butterfield in his Origins of Modern Science . Thomas Kuhn 's 1962 work The Structure of Scientific Revolutions emphasizes that different theoretical frameworks—such as Einstein 's theory of relativity and Newton's theory of gravity , which it replaced—cannot be directly compared without meaning loss. The period saw

8370-735: The Association, which asked the French geodesists to take part in its work. It was only after the Franco-Prussian War , that Charles-Eugène Delaunay represented France at the Congress of Vienna in 1871. In 1874, Hervé Faye was appointed member of the Permanent Commission which was presided by Carlos Ibáñez e Ibáñez de Ibero. After the French Revolution , Napoleonic Wars led to the adoption of

8525-514: The Committee Meter were replaced from 1889 at the initiative of the International Geodetic Association by thirty platinum-iridium bars kept across the globe. A better standardization 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. Progress in science finally allowed

8680-480: 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. The construction of the international prototype metre and the copies which were

8835-517: The Fall together with man's original purity. In this way, he believed, would mankind be raised above conditions of helplessness, poverty and misery, while coming into a condition of peace, prosperity and security. For this purpose of obtaining knowledge of and power over nature, Bacon outlined in this work a new system of logic he believed to be superior to the old ways of syllogism , developing his scientific method, consisting of procedures for isolating

8990-486: 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: " A tous les temps, à tous les peuples " (For all times, to all peoples); and this deed consisted in the approval and distribution, among the governments of the states supporting

9145-503: The Metre Convention, of prototype standards of hitherto unknown precision intended to propagate the metric unit throughout the whole world. 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

9300-749: The National Archives. Besides the latter, another platinum and twelve iron standards of the metre were made by Étienne Lenoir in 1799. One of them became known as the Committee Meter in the United States and served as standard of length in the United States Coast Survey 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

9455-414: 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

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9610-458: The Principles of Hydrostatics') published in 1743, Alexis Claude Clairaut synthesized the relationships existing between gravity and the shape of the Earth. Clairaut exposed there his theorem which established a relationship between gravity measured at different latitudes and the flattening of the Earth considered as a spheroid composed of concentric layers of variable densities. Towards

9765-400: The Scientific Revolution, include: Ancient precedent existed for alternative theories and developments which prefigured later discoveries in the area of physics and mechanics; but in light of the limited number of works to survive translation in a period when many books were lost to warfare, such developments remained obscure for centuries and are traditionally held to have had little effect on

9920-716: The Swiss physicist Charles-Edouard Guillaume , was granted the Nobel Prize in Physics in 1920. Guillaume's Nobel Prize marked the end of an era in which metrology was leaving the field of geodesy to become a technological application of physics . Scientific Revolution The Scientific Revolution was a series of events that marked the emergence of modern science during the early modern period , when developments in mathematics , physics , astronomy , biology (including human anatomy ) and chemistry transformed

10075-588: The Toise of Peru. Among these, the toise of Bessel and the apparatus of Borda were respectively the main references for geodesy in Prussia and in France . 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 thermal expansion into account without measuring

10230-476: The account of the variation of the seconds pendulum's length along the same meridian between Shetland 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. Borda was an avid supporter of decimalisation : he had invented the " repeating circle ", a surveying instrument which allowed

10385-410: 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 metric system in all scientific work. 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

10540-478: The axes of the two central lines marked on the bar of platinum–iridium kept at the Bureau International des Poids et Mesures and declared Prototype of the metre by the 1st  Conférence Générale des Poids et Mesures , 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

10695-532: The commission of the French Academy of Sciences – whose members included Borda , Lagrange , Laplace , Monge and Condorcet – 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,

10850-514: The comparison of that measurement to a value computed on the basis of theory, was largely limited to the mathematical disciplines of astronomy and optics in Europe. In the 16th and 17th centuries, European scientists began increasingly applying quantitative measurements to the measurement of physical phenomena on the Earth. Galileo maintained strongly that mathematics provided a kind of necessary certainty that could be compared to God's: "...with regard to those few [mathematical propositions ] which

11005-441: The course of a major meridian arc back to land where Eratosthenes had founded geodesy . 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 more reliable measurements would have given

11160-547: The creation of a "European international bureau for weights and measures". The intimate relationships that necessarily existed between metrology and geodesy explain that the International Association of Geodesy , 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

11315-446: 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 krypton-86 allowed the standard to be universally available by measurement. In 1983 this was updated to a length defined in terms of the speed of light ; this definition was reworded in 2019: Where older traditional length measures are still used, they are now defined in terms of

11470-433: 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. Christiaan Huygens found out the centrifugal force which explained variations of gravitational acceleration depending on latitude. He also discovered that the seconds pendulum length was a means to measure gravitational acceleration. In

11625-483: 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. Adolphe Hirsch , General Baeyer and Colonel Ibáñez 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

11780-622: The disadvantage of the Conservatoire national des Arts et Métiers . In recognition of France's role in designing the metric system, the BIPM is based in Sèvres , just outside Paris. However, as an international organisation, the BIPM is under the ultimate control of a diplomatic conference, the Conférence générale des poids et mesures (CGPM) rather than the French government. In 1889

11935-441: The earlier, Aristotelian approach of deduction , by which analysis of known facts produced further understanding. In practice, many scientists and philosophers believed that a healthy mix of both was needed—the willingness to question assumptions, yet also to interpret observations assumed to have some degree of validity. By the end of the Scientific Revolution the qualitative world of book-reading philosophers had been changed into

12090-410: 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, Pierre-Simon de Laplace obtained by a calculation taking into account the measures of meridian arcs known at the time a flattening of ⁠ 1 / 279 ⁠ . Gravimetry gave him

12245-481: The establishment of the "universal measure" until the French Revolution 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. Talleyrand resurrected the idea of the seconds pendulum before the Constituent Assembly in 1790, suggesting that

12400-402: The eventual separation of science from both philosophy and religion; a major development in human thought. He was often willing to change his views in accordance with observation. In order to perform his experiments, Galileo had to set up standards of length and time, so that measurements made on different days and in different laboratories could be compared in a reproducible fashion. This provided

12555-432: The far-reaching and world-changing character of inventions, such as the printing press , gunpowder and the compass . Despite his influence on scientific methodology, he rejected correct novel theories such as William Gilbert 's magnetism , Copernicus's heliocentrism, and Kepler's laws of planetary motion . Bacon first described the experimental method . There remains simple experience; which, if taken as it comes,

12710-399: The first symbolic notation of parameters in algebra . Newton's development of infinitesimal calculus opened up new applications of the methods of mathematics to science. Newton taught that scientific theory should be coupled with rigorous experimentation, which became the keystone of modern science. Aristotle recognized four kinds of causes, and where applicable, the most important of them

12865-606: The flattening of the Earth when he proposed his ellipsoid of reference . This was also the result of the Metre Convention 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 Ferdinand Rudolph Hassler later Carl Friedrich Gauss and Carlos Ibáñez e Ibáñez de Ibero . In the 18th century, geodetic surveys found practical applications in French cartography and in

13020-781: The form of the Mètre des Archives , a platinum bar held in Paris. During the mid nineteenth century, following the American Revolution and independence of Latin America , the metre gained adoption in Americas , particularly in scientific usage, and it was officially established as an international measurement unit by the Metre Convention of 1875 at the beginning of the Second Industrial Revolution . The Mètre des Archives and its copies such as

13175-477: The formal cause of a phenomenon (heat, for example) through eliminative induction. For him, the philosopher should proceed through inductive reasoning from fact to axiom to physical law . Before beginning this induction, though, the enquirer must free his or her mind from certain false notions or tendencies which distort the truth. In particular, he found that philosophy was too preoccupied with words, particularly discourse and debate, rather than actually observing

13330-504: The former Portuguese Empire , there were several units called league (Portuguese: légua ): The names of the several léguas referred to the number of units that made the length corresponding to an angle degree of a meridian arc . For compatibility after Portugal adopted the metric system, the metric légua of 5.0 km was used. In Brazil, the léguas is still used occasionally, where it has been described as about 6.6 km. The legua or Spanish league

13485-670: The foundation of a World institute for the comparison of geodetic standards, the first step towards the creation of the International Bureau of Weights and Measures . Hassler's metrological and geodetic work also had a favourable response in Russia. In 1869, the Saint Petersburg Academy of Sciences sent to the French Academy of Sciences a report drafted by Otto Wilhelm von Struve , Heinrich von Wild , and Moritz von Jacobi , whose theorem has long supported

13640-405: The foundations of the metric system , 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

13795-643: 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: Mitteleuropaïsche Gradmessung ) on the initiative of Johann Jacob Baeyer in 1863, and by that of the International Meteorological Organisation whose president, the Swiss meteorologist and physicist, Heinrich von Wild would represent Russia at

13950-469: The human intellect does understand, I believe its knowledge equals the Divine in objective certainty..." Galileo anticipates the concept of a systematic mathematical interpretation of the world in his book Il Saggiatore : Philosophy [i.e., physics] is written in this grand book—I mean the universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend

14105-478: The human mind was that which was based on experience. He wrote that the human mind was created as a tabula rasa , a "blank tablet," upon which sensory impressions were recorded and built up knowledge through a process of reflection. The philosophical underpinnings of the Scientific Revolution were laid out by Francis Bacon, who has been called the father of empiricism. His works established and popularised inductive methodologies for scientific inquiry, often called

14260-440: The 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,

14415-629: The introduction of the Metric Act of 1866 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 European Arc Measurement (German: Europäische Gradmessung ) to establish a "European international bureau for weights and measures". In 1867 at the second General Conference of the International Association of Geodesy held in Berlin,

14570-515: The job was given to the London firm of Johnson Matthey who succeeded in producing thirty bars to the required specification. One of these, No. 6, was determined to be identical in length to the mètre des Archives , 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

14725-400: The language and interpret the characters in which it is written. It is written in the language of mathematics , and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth. In 1591 François Viète published In Artem Analyticem Isagoge , which gave

14880-461: The leading figures in the scientific revolution imagined themselves to be champions of a science that was more compatible with Christianity than the medieval ideas about the natural world that they replaced. The Scientific Revolution was built upon the foundation of ancient Greek learning and science in the Middle Ages, as it had been elaborated and further developed by Roman/Byzantine science and medieval Islamic science . Some scholars have noted

15035-453: The length of the pendulum. In 1645 Giovanni Battista Riccioli was the first to determine the length of a " seconds pendulum " (a pendulum with a half-period of one second ). Kepler's laws of planetary motion served both to the discovery of Newton's law of universal gravitation and to the determination of the distance from Earth to the Sun by Giovanni Domenico Cassini . They both also used

15190-430: The length standards in various European cities. For example, the Paris toise included six Paris feet , while the English yard measured three London feet. Scientific revolution began with Copernicus work. Galileo discovered gravitational acceleration explaining the fall of bodies at the surface of the Earth. He also observed the regularity of the period of swing of the pendulum and that this period depended on

15345-708: The main architects of the Metre Convention. In the 1870s, German Empire played a pivotal role in the unification of the metric system through the European Arc Measurement but its overwhelming influence was mitigated by that of neutral states. While the German astronomer Wilhelm Julius Foerster along with the Russian and Austrian representatives boycotted the Permanent Committee of the International Metre Commission in order to prompt

15500-555: The material world: "For while men believe their reason governs words, in fact, words turn back and reflect their power upon the understanding, and so render philosophy and science sophistical and inactive." Bacon considered that it is of greatest importance to science not to keep doing intellectual discussions or seeking merely contemplative aims, but that it should work for the bettering of mankind's life by bringing forth new inventions, even stating "inventions are also, as it were, new creations and imitations of divine works". He explored

15655-594: The method of calculating the length of the Paris meridian were taken into account by Bessel when he proposed his reference ellipsoid in 1841. Egyptian astronomy has ancient roots which were revived in the 19th century by the modernist impetus of Muhammad Ali who founded in Sabtieh, Boulaq district, in Cairo an Observatory which he was keen to keep in harmony with the progress of this science still in progress. In 1858,

15810-602: The metre in Latin America following independence of Brazil and Hispanic America , while the American Revolution prompted the foundation of the Survey of the Coast in 1807 and the creation of the Office of Standard Weights and Measures in 1830. During the mid nineteenth century, following the defeat and expulsion of Napoleon Bonaparte 's forces which brought an end to the short-lived French occupation of Lower Egypt ,

15965-633: The metre was adopted in Khedivate of Egypt an autonomous tributary state of the Ottoman Empire for the cadastre work. In continental Europe , metrication and a better standardization of units of measurement respectively followed the successive fall of First French Empire in 1815 and Second French Empire defeated in the Franco-Prussian War (1870–1871). Napoleonic Wars fostered German nationalism which later led to unification of Germany in 1871. Meanwhile most European countries had adopted

16120-403: The metre was preserved to within 0.2 μm. At this time, it was decided that a more formal definition of the metre was 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. The unit of length is the metre, defined by the distance, at 0°, between

16275-492: The metre – for example the yard has since 1959 officially been defined as exactly 0.9144 metre. The Nippur cubit 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 bar

16430-612: The metre-alloy of 1874, a member of the Preparatory Committee since 1870 and Spanish representative at the Paris Conference in 1875, Carlos Ibáñez e Ibáñez de Ibero intervened with the French Academy of Sciences 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 metric system according to

16585-524: The metre. The 1870s marked the beginning of the Technological Revolution a period in which German Empire would challenge Britain as the foremost industrial nation in Europe. This was accompanied by development in cartography which was a prerequisit for both military operations and the creation of the infrastructures needed for industrial development such as railways . During the process of unification of Germany , geodesists called for

16740-431: The national standards was at the limits of the technology of the time. The bars were made of a special alloy, 90%  platinum and 10%  iridium , which was significantly harder than pure platinum, and have a special X-shaped cross section (a " Tresca section ", named after French engineer Henri Tresca ) to minimise the effects of torsional strain during length comparisons. The first castings proved unsatisfactory, and

16895-456: 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. This option, with one-third of this length defining the foot , was also considered by Thomas Jefferson and others for redefining the yard in the United States shortly after gaining independence from

17050-415: 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 thermometry work led to the discovery of special alloys of iron–nickel, in particular invar , whose practically negligible coefficient of expansion made it possible to develop simpler baseline measurement methods, and for which its director,

17205-518: The only problems the surveyors had to face in the convulsed period of the aftermath of the Revolution: Méchain and Delambre, and later Arago , were imprisoned several times during their surveys, and Méchain died in 1804 of yellow fever , 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  lignes . This value

17360-449: The participation of about thirty countries. At that time, units of measurement were defined by primary standards , and unique artifacts made of different alloys with distinct coefficients of expansion were the legal basis of units of length. A wrought iron ruler, the Toise of Peru, also called Toise de l'Académie , was the French primary standard of the toise, and the metre was officially defined by an artifact made of platinum kept in

17515-445: The prevailing Aristotelian philosophy and the scholastic method of university teaching. His book De Magnete was written in 1600, and he is regarded by some as the father of electricity and magnetism. In this work, he describes many of his experiments with his model Earth called the terrella . From these experiments, he concluded that the Earth was itself magnetic and that this was the reason compasses point north. De Magnete

17670-484: The progress of sciences. The Metre Convention was signed on 20 May 1875 in Paris and the International Bureau of Weights and Measures was created under the supervision of the International Committee for Weights and Measures . At the session on 12 October 1872 of the Permanent Committee of the International Metre Commission, which was to become the International Committee for Weights and Measures , Carlos Ibáñez e Ibáñez de Ibero had been elected president. His presidency

17825-468: 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 preliminary proposal made in Neuchâtel 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

17980-583: The re-discovery of such phenomena; whereas the invention of the printing press made the wide dissemination of such incremental advances of knowledge commonplace. Meanwhile, however, significant progress in geometry, mathematics, and astronomy was made in medieval times. It is also true that many of the important figures of the Scientific Revolution shared in the general Renaissance respect for ancient learning and cited ancient pedigrees for their innovations. Copernicus, Galileo, Johannes Kepler and Newton all traced different ancient and medieval ancestries for

18135-413: The rest," and "nature can only be commanded by obeying her". Here is an abstract of the philosophy of this work, that by the knowledge of nature and the using of instruments, man can govern or direct the natural work of nature to produce definite results. Therefore, that man, by seeking knowledge of nature, can reach power over it—and thus reestablish the "Empire of Man over creation," which had been lost by

18290-492: The results of the French Geodetic Mission to Lapland had been excluded, whereas a value close to ⁠ 1 / 300 ⁠ would have been found, if they had been combined with those of the French Geodetic Mission to the Equator . In 1841, Friedrich Wilhelm Bessel would calculate the Earth's flattening from ten meridian arcs measured with sufficient accuracy using the method of least squares and found

18445-529: The reunion of the Diplomatic Conference of the Metre and to promote the foundation of a permanent International Bureau of Weights and Measures , Adolphe Hirsch , 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

18600-501: The rise of Christianity and reduces the Renaissance and Reformation to the rank of mere episodes, mere internal displacements within the system of medieval Christendom.... [It] looms so large as the real origin both of the modern world and of the modern mentality that our customary periodization of European history has become an anachronism and an encumbrance. Historian Peter Harrison attributes Christianity to having contributed to

18755-565: The rise of the Scientific Revolution: historians of science have long known that religious factors played a significantly positive role in the emergence and persistence of modern science in the West. Not only were many of the key figures in the rise of science individuals with sincere religious commitments, but the new approaches to nature that they pioneered were underpinned in various ways by religious assumptions. ... Yet, many of

18910-614: The salient point is that Newton's theory differed from ancient understandings in key ways, such as an external force being a requirement for violent motion in Aristotle's theory. Under the scientific method as conceived in the 17th century, natural and artificial circumstances were set aside as a research tradition of systematic experimentation was slowly accepted by the scientific community. The philosophy of using an inductive approach to obtain knowledge—to abandon assumption and to attempt to observe with an open mind—was in contrast with

19065-759: The science of motion. The Scientific Revolution was enabled by advances in book production. Before the advent of the printing press , introduced in Europe in the 1440s by Johannes Gutenberg , there was no mass market on the continent for scientific treatises, as there had been for religious books. Printing decisively changed the way scientific knowledge was created, as well as how it was disseminated. It enabled accurate diagrams, maps, anatomical drawings, and representations of flora and fauna to be reproduced, and printing made scholarly books more widely accessible, allowing researchers to consult ancient texts freely and to compare their own observations with those of fellow scholars. Although printers' blunders still often resulted in

19220-413: 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 0.999 9984 m ± 0.2 μm (1.6 μm short of the international prototype). 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

19375-673: The spread of false data (for instance, in Galileo's Sidereus Nuncius (The Starry Messenger), published in Venice in 1610, his telescopic images of the lunar surface mistakenly appeared back to front), the development of engraved metal plates allowed accurate visual information to be made permanent, a change from previously, when woodcut illustrations deteriorated through repetitive use. The ability to access previous scientific research meant that researchers did not have to always start from scratch in making sense of their own observational data. In

19530-432: The standard theory of the history of the Scientific Revolution claims that the 17th century was a period of revolutionary scientific changes. Not only were there revolutionary theoretical and experimental developments, but that even more importantly, the way in which scientists worked was radically changed. For instance, although intimations of the concept of inertia are suggested sporadically in ancient discussion of motion,

19685-520: The study, in Europe, of the precision apparatus calibrated against the metre intended to measure the geodesic bases and already built by Jean Brunner 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 Carlos Ibáñez e Ibáñez de Ibero and Frutos Saavedra Meneses

19840-408: The temperature. A French scientific instrument maker, Jean Nicolas Fortin , had made three direct copies of the Toise of Peru, one for Friedrich Georg Wilhelm von Struve , a second for Heinrich Christian Schumacher in 1821 and a third for Friedrich Bessel in 1823. In 1831, Henri-Prudence Gambey also realized a copy of the Toise of Peru which was kept at Altona Observatory . In the second half of

19995-524: The toise constructed in 1735 for the French Geodesic Mission to the Equator , 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 Altona and Koenigsberg Observatories, which he had compared to each other about 1840. This assertion was particularly worrying, because when the primary Imperial yard standard had partially been destroyed in 1834,

20150-543: The unit of length for geodesy in the United States. 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 United States at that time and measured coefficients of expansion to assess temperature effects on the measurements. In 1832, Carl Friedrich Gauss studied the Earth's magnetic field and proposed adding

20305-462: The value of Earth radius as Picard had calculated it. According to Alexis Clairaut , the study of variations in gravitational acceleration was a way to determine the figure of the Earth , whose crucial parameter was the flattening of the Earth ellipsoid . In his famous work Théorie de la figure de la terre, tirée des principes de l'hydrostatique ('Theory of the Figure of the Earth, drawn from

20460-483: The various complex systems of subdivision then in use, they also preferred a decimal system to ease their calculations. With the French Revolution (1789) came a desire to replace many features of the Ancien Régime , including the traditional units of measure . As a base unit of length, many scientists had favoured the seconds pendulum (a pendulum with a half-period of one second) one century earlier, but this

20615-588: The views of society about nature. The Scientific Revolution took place in Europe in the second half of the Renaissance period, with the 1543 Nicolaus Copernicus publication De revolutionibus orbium coelestium ( On the Revolutions of the Heavenly Spheres ) often cited as its beginning. The Scientific Revolution has been called "the most important transformation in human history" since

20770-474: The wisdom of the past, to a fervid expectation of change and improvement." This gave rise to the common view of the Scientific Revolution today: A new view of nature emerged, replacing the Greek view that had dominated science for almost 2,000 years. Science became an autonomous discipline, distinct from both philosophy and technology, and came to be regarded as having utilitarian goals. The Scientific Revolution

20925-439: The world was through observation and searching for "natural" circumstances through reasoning. Coupled with this approach was the belief that rare events which seemed to contradict theoretical models were aberrations, telling nothing about nature as it "naturally" was. During the Scientific Revolution, changing perceptions about the role of the scientist in respect to nature, the value of evidence, experimental or observed, led towards

21080-523: Was appointed first Superintendent of the Survey of the Coast . Trained in geodesy in Switzerland, France and Germany , Hassler had brought a standard metre made in Paris to the United States in October 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

21235-673: 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 Borda '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 Struve Geodetic Arc with an arc running northwards from South Africa through Egypt would bring

21390-656: 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, Wilhelm Julius Foerster , director of the Berlin Observatory and director of the German Weights and Measures Service, the Swiss meteorologist and physicist , Heinrich von Wild representing Russia, and the Swiss geodesist of German origin, Adolphe Hirsch were also among

21545-402: Was described as a rationalist. Thomas Hobbes , George Berkeley , and David Hume were the philosophy's primary exponents who developed a sophisticated empirical tradition as the basis of human knowledge. An influential formulation of empiricism was John Locke 's An Essay Concerning Human Understanding (1689), in which he maintained that the only true knowledge that could be accessible to

21700-520: 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 Alps , in order to determine the influence of this mountain range on vertical deflection . Baeyer also planned to determine the curvature of the seas, the Mediterranean Sea and Adriatic Sea in the south,

21855-783: Was discovered in Nippur , on the banks of the Euphrates , and is kept in the Istanbul Archaeological Museum . Archaeologists consider that this 51.85 cm long unit was the origin of the Roman foot . Indeed, the Egyptians divided the Sumerian cubit into 28 fingers and 16 of these fingers gave a Roman foot of 29.633 cm. The Roman foot was divided into 4 palms , 12 inches or 16 fingers . A Roman cubit

22010-529: Was discovered that the length of a seconds pendulum varies from place to place: French astronomer Jean Richer had measured the 0.3% difference in length between Cayenne (in French Guiana) and Paris. Jean Richer and Giovanni Domenico Cassini measured the parallax of Mars between Paris and Cayenne in French Guiana when Mars was at its closest to Earth in 1672. They arrived at a figure for

22165-524: Was equivalent to 1.5 feet, a pace to 5 feet. A Roman mile contained 1000 paces or 5000 feet. A Roman league 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 lines of 6 points each. Multiples of these feet became

22320-496: Was first used in Switzerland by Emile Plantamour , Charles Sanders Peirce and Isaac-Charles Élisée Cellérier (1818–1889), a Genevan mathematician soon independently discovered a mathematical formula to correct systematic errors of this device which had been noticed by Plantamour and Adolphe Hirsch . This would allow Friedrich Robert Helmert to determine a remarkably accurate value of ⁠ 1 / 298.3 ⁠ for

22475-426: Was influential because of the inherent interest of its subject matter as well as for the rigorous way in which Gilbert describes his experiments and his rejection of ancient theories of magnetism. According to Thomas Thomson , "Gilbert['s]... book on magnetism published in 1600, is one of the finest examples of inductive philosophy that has ever been presented to the world. It is the more remarkable, because it preceded

22630-481: Was later explained by clearance in the central axis of the repeating circle causing wear and consequently the zenith measurements contained significant systematic errors. Polar motion predicted by Leonhard Euler and later discovered by Seth Carlo Chandler also had an impact on accuracy of latitudes' determinations. Among all these sources of error, it was mainly an unfavourable vertical deflection that gave an inaccurate determination of Barcelona's latitude and

22785-471: Was necessary to carefully study considerable areas of land in all directions. Baeyer developed a plan to coordinate geodetic surveys in the space between the parallels of Palermo and Freetown Christiana ( Denmark ) and the meridians of Bonn and Trunz (German name for Milejewo in Poland ). This territory was covered by a triangle network and included more than thirty observatories or stations whose position

22940-563: Was one of the first modern thinkers to clearly state that the laws of nature are mathematical. In The Assayer he wrote "Philosophy is written in this grand book, the universe ... It is written in the language of mathematics, and its characters are triangles, circles, and other geometric figures;...." His mathematical analyses are a further development of a tradition employed by late scholastic natural philosophers, which Galileo learned when he studied philosophy. He ignored Aristotelianism. In broader terms, his work marked another step towards

23095-487: Was originally understood as equivalent to 3 millas (Spanish miles ). This varied depending on local standards for the pie (Spanish foot ) and on the precision of measurement, but was officially equivalent to 4,180 metres (2.6 miles ) before the legua was abolished by Philip II in 1568. It remains in use in parts of Latin America , where its exact meaning varies. In the early Hispanic settlements of New Mexico , Texas , California , and Colorado ,

23250-457: 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. The question of measurement reform was placed in the hands of the Academy of Sciences , who appointed a commission chaired by Jean-Charles de Borda . Instead of the seconds pendulum method,

23405-409: Was rejected as it had been discovered that this length varied from place to place with local gravity. A new unit of length, the metre was introduced – defined as one ten-millionth of the shortest distance from the North Pole to the equator passing through Paris , assuming an Earth flattening of ⁠ 1 / 334 ⁠ . The historical French official standard of the metre was made available in

23560-574: Was run under a set of rules still retained by the Bodleian Library . League (unit) It may have originally represented, roughly, the distance a person could walk in an hour . The league was used in Ancient Rome , defined as 1½ Roman miles (7,500 Roman feet , modern 2.2 km or 1.4 miles). The origin is the leuga Gallica (also: leu c a Callica ) , the league of Gaul . The Argentine league ( legua )

23715-415: Was said in his own life to have created a revolution". The word was also used in the preface to Antoine Lavoisier 's 1789 work announcing the discovery of oxygen. "Few revolutions in science have immediately excited so much general notice as the introduction of the theory of oxygen ... Lavoisier saw his theory accepted by all the most eminent men of his time, and established over a great part of Europe within

23870-472: Was set by legislation on 7 April 1795. The project was split into two parts – the northern section of 742.7 km from the belfry, Dunkirk to Rodez Cathedral which was surveyed by Delambre and the southern section of 333.0 km from Rodez to the Montjuïc Fortress , Barcelona which was surveyed by Méchain. Delambre used a baseline of about 10 km (6,075.90 toises ) in length along

24025-590: Was the Royal Society of London. This grew out of an earlier group, centered around Gresham College in the 1640s and 1650s. According to a history of the college: The scientific network which centered on Gresham College played a crucial part in the meetings which led to the formation of the Royal Society. These physicians and natural philosophers were influenced by the "new science", as promoted by Bacon in his New Atlantis , from approximately 1645 onwards. A group known as The Philosophical Society of Oxford

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