Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography , the two most notable variations being British and American spelling. Many of the differences between American and British or Commonwealth English date back to a time before spelling standards were developed. For instance, some spellings seen as "American" today were once commonly used in Britain, and some spellings seen as "British" were once commonly used in the United States.
179-548: The metre (or meter in US spelling ; symbol: m ) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of 1 / 299 792 458 of a second , where the second is defined by a hyperfine transition frequency of caesium . The metre was originally defined in 1791 by
358-622: 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
537-691: A consonant followed by an unstressed -re (pronounced /ə(r)/ ). In modern American English, most of these words have the ending -er . The difference is most common for words ending in -bre or -tre : British spellings calibre , centre , fibre , goitre , litre , lustre , manoeuvre , meagre , metre (length) , mitre , nitre , ochre , reconnoitre , sabre , saltpetre , sepulchre , sombre , spectre , theatre (see exceptions ) and titre all have -er in American spelling. In Britain, both -re and -er spellings were common before Johnson's 1755 dictionary
716-475: A distinctive set of Canadian English spellings is viewed by many Canadians as one of the unique aspects of Canadian culture (especially when compared to the United States). In Australia, -or endings enjoyed some use throughout the 19th century and in the early 20th century. Like Canada, though, most major Australian newspapers have switched from " -or " endings to " -our " endings. The " -our " spelling
895-495: A emium , and a enigma . In others, it is kept in all varieties: for example, phoenix , and usually subpoena , but Phenix in Virginia . This is especially true of names: Aegean (the sea), Caesar , Oedipus , Phoebe , etc., although "caesarean section" may be spelled as "cesarean section". There is no reduction of Latin -ae plurals (e.g., larv ae ); nor where the digraph <ae>/<oe> does not result from
1074-466: A eon , an a emia , an a esthesia , c a ecum , c a esium , c o eliac , diarrh o ea , encyclop a edia , f a eces , f o etal , gyn a ecology , h a emoglobin , h a emophilia , leuk a emia , o esophagus , o estrogen , orthop a edic , pal a eontology , p a ediatric , p a edophile . Oenology is acceptable in American English but is deemed
1253-586: A letter to the Royal Society of London with his findings. The society published an article in Philosophical Transactions the following year in 1737 that revealed his discovery. Clairaut showed how Newton's equations were incorrect, and did not prove an ellipsoid shape to the Earth. However, he corrected problems with the theory, that in effect would prove Newton's theory correct. Clairaut believed that Newton had reasons for choosing
1432-915: 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
1611-532: A minor variant of enology , whereas although archeology and ameba exist in American English, the British versions amoeba and archaeology are more common. The chemical haem (named as a shortening of h a emoglobin ) is spelled heme in American English, to avoid confusion with hem . Canadian English mostly follows American English in this respect, although it is split on gynecology (e.g. Society of Obstetricians and Gynaecologists of Canada vs.
1790-569: A mistaken etymology. The etymologically correct original spelling fetus reflects the Latin original and is the standard spelling in medical journals worldwide; the Oxford English Dictionary notes that "In Latin manuscripts both fētus and foetus are used". The Ancient Greek diphthongs <αι> and <οι> were transliterated into Latin as <ae> and <oe>. The ligatures æ and œ were introduced when
1969-621: A new value for the flattening of the Earth, which he determinated as 1 / 299.15 . He also devised a new instrument for measuring gravitational acceleration which was first used in Switzerland by Emile Plantamour , Charles Sanders Peirce , and Isaac-Charles Élisée Cellérier (8.01.1818 – 2.10.1889), 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 allowed Friedrich Robert Helmert to determine
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#17327655110142148-708: 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 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
2327-554: 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 General Conference on Weights and Measures (CGPM: Conférence Générale des Poids et Mesures ), establishing the International Prototype Metre as the distance between two lines on a standard bar composed of an alloy of 90% platinum and 10% iridium , measured at
2506-412: A provisional value from older surveys of 443.44 lignes . This value was set by legislation on 7 April 1795. While Méchain and Delambre were completing their survey, the commission had ordered a series of platinum bars to be made based on the provisional metre. When the final result was known, the bar whose length was closest to the meridional definition of the metre was selected and placed in
2685-488: A remarkably accurate value of 1 / 298.3 for the flattening of the Earth when he proposed his ellipsoid of reference in 1901. 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 the example of Ferdinand Rudolph Hassler . In 1790, one year before it
2864-429: A report drafted by Otto Wilhelm von Struve , Heinrich von Wild , and Moritz von Jacobi , 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 metric system in all scientific work. In the 1870s and in light of modern precision, a series of international conferences
3043-582: 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 the 18th century, in addition of 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
3222-625: 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 the unit of length for geodesy in the United States. In 1830, Hassler became head of the Office of Weights and Measures, which became
3401-568: A standard of length. By 1925, interferometry was in regular use at the BIPM. However, the International Prototype Metre remained the standard until 1960, when the eleventh CGPM defined the metre in the new International System of Units (SI) as equal to 1 650 763 .73 wavelengths of the orange - red emission line in the electromagnetic spectrum of the krypton-86 atom in vacuum . To further reduce uncertainty,
3580-423: A standard would be independent of any changes in the dimensions of the earth, and should be adopted by those who expect their writings to be more permanent than that body. Charles Sanders Peirce 's work promoted the advent of American science at the forefront of global metrology. Alongside his intercomparisons of artifacts of the metre and contributions to gravimetry through improvement of reversible pendulum, Peirce
3759-667: A suffix for agentive ( reader , user , winner ) and comparative ( louder , nicer ) forms. One outcome is the British distinction of meter for a measuring instrument from metre for the unit of length. However, while " poetic metre " is often spelled as -re , pentameter , hexameter , etc. are always -er . Many other words have -er in British English. These include Germanic words, such as anger , mother , timber and water , and such Romance-derived words as danger , quarter and river . The ending -cre , as in acre , lucre , massacre , and mediocre ,
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#17327655110143938-432: Is - /s/ for the noun and - /z/ for the verb). For licence / license or practice / practise , British English also keeps the noun–verb distinction graphically (although phonetically the two words in each pair are homophones with - /s/ pronunciation). On the other hand, American English uses license and practice for both nouns and verbs (with - /s/ pronunciation in both cases too). American English has kept
4117-402: Is a pendulum whose period is precisely two seconds ; one second for a swing in one direction and one second for the return swing, a frequency of 0.5 Hz. A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward
4296-681: Is also found in Latin ( metior, mensura ), French ( mètre, mesure ), English and other languages. The Greek word is derived from the Proto-Indo-European root *meh₁- 'to measure'. The motto ΜΕΤΡΩ ΧΡΩ ( metro chro ) in the seal of the International Bureau of Weights and Measures (BIPM), which was a saying of the Greek statesman and philosopher Pittacus of Mytilene and may be translated as "Use measure!", thus calls for both measurement and moderation . The use of
4475-475: Is currently one limiting factor in laboratory realisations of the metre, and it is several orders of magnitude poorer than that of the second, based upon the caesium fountain atomic clock ( U = 5 × 10 ). Consequently, a realisation of the metre is usually delineated (not defined) today in labs as 1 579 800 .762 042 (33) wavelengths of helium–neon laser light in vacuum, the error stated being only that of frequency determination. This bracket notation expressing
4654-399: Is dropped for other derivations, for example, central , fibrous , spectral . However, the existence of related words without e before the r is not proof for the existence of an -re British spelling: for example, entry and entrance come from enter , which has not been spelled entre for centuries. The difference relates only to root words; -er rather than -re is universal as
4833-502: Is generally preferred over oe and often over ae , but oe and ae are sometimes found in academic and scientific writing as well as government publications (for example, the fee schedule of the Ontario Health Insurance Plan ) and some words such as palaeontology or aeon . In Australia, it can go either way, depending on the word: for instance, medieval is spelled with the e rather than ae , following
5012-601: Is known as the Pacific Parlour car, not Pacific Parlor . Proper names such as Pearl Harbor or Sydney Harbour are usually spelled according to their native-variety spelling vocabulary. The name of the herb savory is spelled thus everywhere, although the related adjective savo(u)ry , like savo(u)r , has a u in the UK. Honor (the name) and arbor (the tool) have -or in Britain, as mentioned above, as does
5191-613: Is sometimes used. The ratio between -ise and -ize stood at 3:2 in the British National Corpus up to 2002. The spelling -ise is more commonly used in UK mass media and newspapers, including The Times (which switched conventions in 1992), The Daily Telegraph , The Economist and the BBC . The Government of the United Kingdom additionally uses -ise , stating "do not use Americanisms" justifying that
5370-714: Is standard worldwide and complection is rare. However, the adjective complected (as in "dark-complected"), although sometimes proscribed, is on equal ground in the U.S. with complexioned. It is not used in this way in the UK, although there exists a rare alternative meaning of complicated . In some cases, words with "old-fashioned" spellings are retained widely in the U.S. for historical reasons (cf. connexionalism ). Many words, especially medical words, that are written with ae/æ or oe/œ in British English are written with just an e in American English. The sounds in question are /iː/ or /ɛ/ (or, unstressed, /i/ , /ɪ/ or /ə/ ). Examples (with non-American letter in bold ):
5549-607: Is taught in schools nationwide as part of the Australian curriculum. The most notable countrywide use of the -or ending is for one of the country's major political parties, the Australian Labor Party , which was originally called "the Australian Labour Party" (name adopted in 1908), but was frequently referred to as both "Labour" and "Labor". The "Labor" was adopted from 1912 onward due to
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5728-405: Is the day . Two types of solar time are apparent solar time ( sundial time) and mean solar time (clock time). Mean solar time is the hour angle of the mean Sun plus 12 hours. This 12 hour offset comes from the decision to make each day start at midnight for civil purposes whereas the hour angle or the mean sun is measured from the zenith (noon). The duration of daylight varies during the year but
5907-549: Is the usual form of the male given name, as a surname both the spellings Peter and Petre (the latter notably borne by a British lord ) are found. For British accoutre , the American practice varies: the Merriam-Webster Dictionary prefers the -re spelling, but The American Heritage Dictionary of the English Language prefers the -er spelling. More recent French loanwords keep
6086-427: Is this difference, which is cyclical and does not accumulate from year to year. Mean time follows the mean sun. Jean Meeus describes the mean sun as follows: "Consider a first fictitious Sun travelling along the ecliptic with a constant speed and coinciding with the true sun at the perigee and apogee (when the Earth is in perihelion and aphelion, respectively). Then consider a second fictitious Sun travelling along
6265-484: Is used in both British and American English to show that the c is pronounced /k/ rather than /s/ . The spellings euchre and ogre are also the same in both British and American English. Fire and its associated adjective fiery are the same in both British and American English, although the noun was spelled fier in Old and Middle English. Theater is the prevailing American spelling used to refer to both
6444-591: The -meter suffix (from Ancient Greek - μέτρον métron , via French -mètre ) normally had the -re spelling from earliest use in English but were superseded by -er . Examples include thermometer and barometer . The e preceding the r is kept in American-inflected forms of nouns and verbs, for example, fibers , reconnoitered , centering , which are fibres , reconnoitred , and centring respectively in British English. According to
6623-560: The -ise form as an alternative. Publications by Oxford University Press (OUP)—such as Henry Watson Fowler 's A Dictionary of Modern English Usage , Hart's Rules , and The Oxford Guide to English Usage —also recommend -ize . However, Robert Allan's Pocket Fowler's Modern English Usage considers either spelling to be acceptable anywhere but the U.S. American spelling avoids -ise endings in words like organize , realize and recognize . British spelling mostly uses -ise ( organise , realise , recognise ), though -ize
6802-687: The -ise form is preferred in Australian English at a ratio of about 3:1 according to the Macquarie Dictionary . In Canada, the -ize ending is more common, although the Ontario Public School Spelling Book spelled most words in the -ize form, but allowed for duality with a page insert as late as the 1970s, noting that, although the -ize spelling was in fact the convention used in the OED ,
6981-439: The -ise variation, once more common amongst older Canadians, is employed less and less often in favour of the -ize spelling. (The alternate convention offered as a matter of choice may have been due to the fact that although there were an increasing number of American- and British-based dictionaries with Canadian Editions by the late 1970s, these were largely only supplemental in terms of vocabulary with subsequent definitions. It
7160-450: The -re spelling in American English. These are not exceptions when a French-style pronunciation is used ( /rə/ rather than /ə(r)/ ), as with double entendre , genre and oeuvre . However, the unstressed /ə(r)/ pronunciation of an -er ending is used more (or less) often with some words, including cadre , macabre , maître d' , Notre Dame , piastre , and timbre . The -re endings are mostly standard throughout
7339-640: The British Crown . Instead of the seconds pendulum method, 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 , determined through measurements along the meridian passing through Paris. Apart from
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7518-495: The Canadian Medical Association 's Canadian specialty profile of Obstetrics/gynecology ). Pediatrician is preferred roughly 10 to 1 over paediatrician , while foetal and oestrogen are similarly uncommon. Words that can be spelled either way in American English include a esthetics and arch a eology (which usually prevail over esthetics and archeology ), as well as pal a estra , for which
7697-601: 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 the Toise of Peru. Among these, the toise of Bessel and the apparatus of Borda were respectively
7876-530: The French National Assembly as one ten-millionth of the distance from the equator to the North Pole along a great circle , so the Earth's polar circumference is approximately 40 000 km . In 1799, the metre was redefined in terms of a prototype metre bar, the bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86 . The current definition
8055-651: 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
8234-548: The OED , centring is a "word ... of 3 syllables (in careful pronunciation)" (i.e., /ˈsɛntərɪŋ/ ), yet there is no vowel in the spelling corresponding to the second syllable ( /ə/ ). The OED third edition (revised entry of June 2016) allows either two or three syllables. On the Oxford Dictionaries Online website, the three-syllable version is listed only as the American pronunciation of centering . The e
8413-689: The Organisation for Economic Co-operation and Development ). The European Union 's style guides require the usage of - ise . Proofreaders at the EU's Publications Office ensure consistent spelling in official publications such as the Official Journal of the European Union (where legislation and other official documents are published), but the -ize spelling may be found in other documents. Seconds pendulum A seconds pendulum
8592-557: The Simplified Spelling Board in the early 20th century, but most were not adopted. In Britain, the influence of those who preferred the Norman (or Anglo-French ) spellings of words proved to be decisive. Later spelling adjustments in the United Kingdom had little effect on today's American spellings and vice versa. For the most part, the spelling systems of most Commonwealth countries and Ireland closely resemble
8771-489: The celestial equator at a constant speed and coinciding with the first fictitious Sun at the equinoxes. This second fictitious sun is the mean Sun ..." In 1936 French and German astronomers found that Earth's rotation speed is irregular. Since 1967 atomic clocks define the second. The length of a seconds pendulum was determined (in toises ) by Marin Mersenne in 1644. In 1660, the Royal Society proposed that it be
8950-491: The luminiferous aether in 1905, just as Newton had questioned Descartes' Vortex theory in 1687 after Jean Richer 's pendulum experiment in Cayenne , French Guiana . Furthermore, special relativity changed conceptions of time and mass , while general relativity changed that of space . According to Newton, space was Euclidean , infinite and without boundaries and bodies gravitated around each other without changing
9129-460: 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
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#17327655110149308-509: 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 the value of Earth radius as Picard had calculated it. The English physicist Sir Isaac Newton , who used Picard's Earth measurement for establishing his law of universal gravity , explained this variation of
9487-619: 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 the value of Earth radius as Picard had calculated it. After the Anglo-French Survey , the French Academy of Sciences commissioned an expedition led by Jean Baptiste Joseph Delambre and Pierre Méchain , lasting from 1792 to 1798, which measured
9666-480: The theatre spelling. (The word "theater" in American English is a place where both stage performances and screenings of films take place, but in British English a "theatre" is where stage performances take place but not film screenings – these take place in a cinema, or "picture theatre" in Australia.) In the United States, the spelling theatre is sometimes used when referring to the art form of theatre, while
9845-519: The u has since been dropped: ambassadour , emperour , errour , governour , horrour , inferiour , mirrour , perturbatour , superiour , tenour , terrour , tremour . Johnson, unlike Webster, was not an advocate of spelling reform, but chose the spelling best derived, as he saw it, from among the variations in his sources. He preferred French over Latin spellings because, as he put it, "the French generally supplied us". English speakers who moved to
10024-435: The u : In American usage, derivatives and inflected forms are built by simply adding the suffix in all cases (for example, favorite , savory etc.) since the u is absent to begin with. American usage, in most cases, keeps the u in the word glamour , which comes from Scots , not Latin or French. Glamor is sometimes used in imitation of the spelling reform of other -our words to -or . Nevertheless,
10203-652: The ‑our/or group do not have a Latin counterpart that ends in ‑or ; for example, armo(u)r , behavio(u)r , harbo(u)r , neighbo(u)r ; also arbo(u)r , meaning "shelter", though senses "tree" and "tool" are always arbor , a false cognate of the other word. The word arbor would be more accurately spelled arber or arbre in the US and the UK, respectively, the latter of which is the French word for "tree". Some 16th- and early 17th-century British scholars indeed insisted that ‑or be used for words from Latin (e.g., color ) and ‑our for French loans; however, in many cases,
10382-476: The 0.3% difference in length between Cayenne (in what is now 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 the solar parallax of 9.5 arcseconds, equivalent to an Earth–Sun distance of about 22000 Earth radii. They were also
10561-432: 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 a different value for the definition of this international standard. That does not invalidate the metre in any way but highlights
10740-510: The 17th CGPM in 1983 replaced the definition of the metre with its current definition, thus fixing the length of the metre in terms of the second and the speed of light : This definition fixed the speed of light in vacuum at exactly 299 792 458 metres per second (≈ 300 000 km/s or ≈1.079 billion km/hour). An intended by-product of the 17th CGPM's definition was that it enabled scientists to compare lasers accurately using frequency, resulting in wavelengths with one-fifth
10919-441: The 17th and 18th centuries, whereas there are thousands of examples of their -our counterparts. One notable exception is honor . Honor and honour were equally frequent in Britain until the 17th century; honor only exists in the UK now as the spelling of Honor Oak , a district of London, and of the occasional given name Honor . In derivatives and inflected forms of the -our/or words, British usage depends on
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#173276551101411098-626: The 1860s, at the initiative of Carlos Ibáñez e Ibáñez de Ibero who would become the first president of both the International Geodetic Association and the International Committee for Weights and Measure , to remeasure the arc of meridian from Dunkirk to Formentera and to extend it from Shetland to the Sahara . This did not pave the way to a new definition of the metre because it was known that
11277-615: The 1970s, but had by then been overtaken by connection in regular usage (for example, in more popular newspapers). Connexion (and its derivatives connexional and connexionalism ) is still in use by the Methodist Church of Great Britain to refer to the whole church as opposed to its constituent districts, circuits and local churches, whereas the US-majority United Methodist Church uses Connection . Complexion (which comes from complex )
11456-593: 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, 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
11635-743: The American National Theatre was referred to by The New York Times as the "American National Theater ", but the organization uses "re" in the spelling of its name. The John F. Kennedy Center for the Performing Arts in Washington, D.C. has the more common American spelling theater in its references to the Eisenhower Theater, part of the Kennedy Center. Some cinemas outside New York also use
11814-480: The American and British varieties of English. However, English-language spelling reform has rarely been adopted otherwise. As a result, modern English orthography varies only minimally between countries and is far from phonemic in any country. In the early 18th century, English spelling was inconsistent. These differences became noticeable after the publication of influential dictionaries . Today's British English spellings mostly follow Johnson's A Dictionary of
11993-413: The American usage along with numerous other words such as eon or fetus , while other words such as oestrogen or paediatrician are spelled the British way. The Macquarie Dictionary also notes a growing tendency towards replacing ae and oe with e worldwide and with the exception of manoeuvre, all British or American spellings are acceptable variants. Elsewhere, the British usage prevails, but
12172-587: The Anglo-French spelling for defense and offense , which are defence and offence in British English. Likewise, there are the American pretense and British pretence ; but derivatives such as defensive , offensive , and pretension are always thus spelled in both systems. Australian and Canadian usages generally follow British usage. The spelling connexion is now rare in everyday British usage, its use lessening as knowledge of Latin attenuates, and it has almost never been used in
12351-665: 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. The International Geodetic Association gained global importance with
12530-440: The British system. In Canada, the spelling system can be said to follow both British and American forms, and Canadians are somewhat more tolerant of foreign spellings when compared with other English-speaking nationalities. Australian English mostly follows British spelling norms but has strayed slightly, with some American spellings incorporated as standard. New Zealand English is almost identical to British spelling, except in
12709-403: The British usage of -our . This coincided with a renewed interest in Canadian English, and the release of the updated Gage Canadian Dictionary in 1997 and the first Canadian Oxford Dictionary in 1998. Historically, most libraries and educational institutions in Canada have supported the use of the Oxford English Dictionary rather than the American Webster's Dictionary . Today, the use of
12888-646: 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 the International Committee for Weights and Measures (CIPM). In 1834, Hassler, measured at Fire Island
13067-524: The Commonwealth. The -er spellings are recognized as minor variants in Canada, partly due to United States influence. They are sometimes used in proper names (such as Toronto's controversially named Centerpoint Mall ). For advice / advise and device / devise , American English and British English both keep the noun–verb distinction both graphically and phonetically (where the pronunciation
13246-531: The Earth's rotation, it follows that the resulting acceleration towards the ground is 0.5% greater at the poles than at the Equator and that the polar diameter of the Earth is smaller than its equatorial diameter. The Academy of Sciences planned to infer the flattening of the Earth from the length's differences between meridional portions corresponding to one degree of latitude . Pierre Méchain and Jean-Baptiste Delambre combined their measurements with
13425-521: The English Language (1755), while many American English spellings follow Webster's An American Dictionary of the English Language ("ADEL", "Webster's Dictionary", 1828). Webster was a proponent of English spelling reform for reasons both philological and nationalistic. In A Companion to the American Revolution (2008), John Algeo notes: "it is often assumed that characteristically American spellings were invented by Noah Webster. He
13604-688: The Equator . 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. In 1816, Ferdinand Rudolph Hassler was appointed first Superintendent of the Survey of the Coast . Trained in geodesy in Switzerland, France and Germany , Hassler had brought
13783-655: The German born, Swiss astronomer, Adolphe Hirsch 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 disadventage of the Conservatoire national des Arts et Métiers . At that time, units of measurement were defined by primary standards , and unique artifacts made of different alloys with distinct coefficients of expansion were
13962-488: The Greek-style ligature as, for example, in maelstrom or toe ; the same is true for the British form aeroplane (compare other aero- words such as aerosol ) . The now chiefly North American airplane is not a respelling but a recoining, modelled after airship and aircraft . The word airplane dates from 1907, at which time the prefix aero- was trisyllabic, often written aëro- . In Canada, e
14141-520: 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 the globe stimulated the creation of the first international scientific associations. The foundation of the Magnetischer Verein would be followed by that of
14320-542: The North Pole to the Equator was then extrapolated from the measurement of the Paris meridian arc between Dunkirk and Barcelona and was determined as 5 130 740 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 French Geodesic Mission to
14499-731: 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 the course of a major meridian arc back to land where Eratosthenes had founded geodesy . Seventeen years after Bessel calculated his ellipsoid of reference , some of
14678-587: 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 . In 1921, the Nobel Prize in Physics was awarded to another Swiss scientist, Albert Einstein , who following Michelson–Morley experiment had questioned
14857-491: 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 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
15036-501: The Toise of Peru. The Toise of Peru had been constructed in 1735 as the standard of reference in the Spanish-French Geodesic Mission , conducted in actual Ecuador from 1735 to 1744. Jean-Baptiste Biot and François Arago published 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
15215-596: The US: the more common connection has become the standard worldwide. According to the Oxford English Dictionary , the older spelling is more etymologically conservative, since the original Latin word had -xio- . The American usage comes from Webster , who abandoned -xion and preferred -ction . Connexion was still the house style of The Times of London until the 1980s and was still used by Post Office Telecommunications for its telephone services in
15394-631: The United States and the Philippines which use meter . Measuring devices (such as ammeter , speedometer ) are spelled "-meter" in all variants of English. The suffix "-meter" has the same Greek origin as the unit of length. The etymological roots of metre can be traced to the Greek verb μετρέω ( metreo ) ((I) measure, count or compare) and noun μέτρον ( metron ) (a measure), which were used for physical measurement, for poetic metre and by extension for moderation or avoiding extremism (as in "be measured in your response"). This range of uses
15573-497: The United States took these preferences with them. In the early 20th century, H. L. Mencken notes that " honor appears in the 1776 Declaration of Independence , but it seems to have been put there rather by accident than by design". In Jefferson 's original draft it is spelled "honour". In Britain, examples of behavior , color , flavor , harbor , and neighbor rarely appear in Old Bailey court records from
15752-423: The United States use Centre in their names. Examples include the villages of Newton Centre and Rockville Centre , the city of Centreville , Centre County and Centre College . Sometimes, these places were named before spelling changes but more often the spelling serves as an affectation. Proper names are usually spelled according to their native-variety spelling vocabulary; so, for instance, although Peter
15931-655: The accession of Chile , Mexico and Japan in 1888; Argentina and United-States in 1889; and British Empire in 1898. The convention of the International Geodetic Association expired at the end of 1916. It was not renewed due to the First World War . However, the activities of the International Latitude Service were continued through an Association Géodesique réduite entre États neutres thanks to
16110-507: The account of the variation of the seconds pendulum's length along the same meridian between Shetland and the Baleares. The seconds pendulum's length is a mean to measure g , the local acceleration due to local gravity and centrifugal acceleration, which varies depending on one's position on Earth (see Earth's gravity ). The task of surveying the Paris meridian arc took more than six years (1792–1798). The technical difficulties were not
16289-617: The adjective glamorous often drops the first "u". Saviour is a somewhat common variant of savior in the US. The British spelling is very common for honour (and favour ) in the formal language of wedding invitations in the US. The name of the Space Shuttle Endeavour has a u in it because the spacecraft was named after British Captain James Cook 's ship, HMS Endeavour . The (former) special car on Amtrak 's Coast Starlight train
16468-522: The amplitude (width) of the pendulum's swing. For a point mass on a weightless string of length L swinging with an infinitesimally small amplitude, without resistance, the length of the string of a seconds pendulum is equal to L = g / π where g is the acceleration due to gravity, with units of length per second squared, and L is the length of the string in the same units. Using the SI recommended acceleration due to gravity of g 0 = 9.80665 m/s ,
16647-474: The anchor escapement and is now used in most modern pendulum clocks. The observation that pendulum clocks slowed down in summer brought the realisation that thermal expansion and contraction of the pendulum rod with changes in temperature was a source of error. This was solved by the invention of temperature-compensated pendulums; the mercury pendulum by George Graham in 1721 and the gridiron pendulum by John Harrison in 1726. With these improvements, by
16826-577: The anchor's narrow pendulum swing allowed the clock's case to accommodate longer, slower pendulums, which needed less power and caused less wear on the movement. The seconds pendulum (also called the Royal pendulum), 0.994 m (39.1 in) long, in which each swing takes one second, became widely used in quality clocks. The long narrow clocks built around these pendulums, first made by William Clement around 1680, became known as grandfather clocks . The increased accuracy resulting from these developments caused
17005-518: The building itself, as noted above, generally is spelled theater . For example, the University of Wisconsin–Madison has a "Department of Theatre and Drama", which offers courses that lead to the "Bachelor of Arts in Theatre ", and whose professed aim is "to prepare our graduate students for successful 21st Century careers in the theatre both as practitioners and scholars". Some placenames in
17184-445: 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
17363-456: The choice to spell such words in the -ise form was a matter of personal preference ; however, a pupil having made the decision, one way or the other, thereafter ought to write uniformly not only for a given word, but to apply that same uniformity consistently for all words where the option is found. Just as with -yze spellings, however, in Canada the ize form remains the preferred or more common spelling, though both can still be found, yet
17542-465: The clock. Huygens was inspired by investigations of pendulums by Galileo Galilei beginning around 1602. Galileo discovered the key property that makes pendulums useful timekeepers: isochronism , which means that the period of swing of a pendulum is approximately the same for different sized swings. Galileo had the idea for a pendulum clock in 1637, which was partly constructed by his son in 1649, but neither lived to finish it. The introduction of
17721-426: The close historic, economic, and cultural relationship with the United States, -or endings are also sometimes used. Throughout the late 19th and early to mid-20th century, most Canadian newspapers chose to use the American usage of -or endings, originally to save time and money in the era of manual movable type . However, in the 1990s, the majority of Canadian newspapers officially updated their spelling policies to
17900-464: The creation of the Office of Standard Weights and Measures in 1830. In continental Europe , Napoleonic Wars fostered German nationalism which later led to unification of Germany in 1871. Meanwhile, most European countries had adopted the metre. 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
18079-580: The creation of the Office of Standard Weights and Measures as an office within the Coast Survey contributed to 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
18258-531: The determination of the distance from Earth to the Sun by Giovanni Domenico Cassini . They both also used 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 ). In 1675, Tito Livio Burattini suggested
18437-418: 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 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
18616-618: The distance between a belfry in Dunkirk and Montjuïc castle in Barcelona at the longitude of the Paris Panthéon . When the length of the metre was defined as one ten-millionth of the distance from the North Pole to the Equator , the flattening of the Earth ellipsoid was assumed to be 1 / 334 . In 1841, Friedrich Wilhelm Bessel using the method of least squares calculated from several arc measurements
18795-403: The dramatic arts and buildings where stage performances and screenings of films take place (i.e., " movie theaters "); for example, a national newspaper such as The New York Times would use theater in its entertainment section. However, the spelling theatre appears in the names of many New York City theatres on Broadway (cf. Broadway theatre) and elsewhere in the United States. In 2003,
18974-491: The effects of the Earth's oblateness were expected to be the largest. The Spanish-French geodetic mission combined with an earlier measurement of the Paris meridian arc and the Lapland geodetic mission had confirmed that the Earth was an oblate spheroid. Moreover, observations were made with a pendulum to determine the local acceleration due to local gravity and centrifugal acceleration; and these observations coincided with
19153-608: The efforts of H.G. van de Sande Bakhuyzen and Raoul Gautier (1854–1931), respectively directors of Leiden Observatory and Geneva Observatory . After the French Revolution , Napoleonic Wars led to the adoption of 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
19332-715: The ending became ‑our to match the later Old French spelling. The ‑our ending was used not only in new English borrowings, but was also applied to the earlier borrowings that had used ‑or . However, ‑or was still sometimes found. The first three folios of Shakespeare 's plays used both spellings before they were standardised to ‑our in the Fourth Folio of 1685. After the Renaissance , new borrowings from Latin were taken up with their original ‑or ending, and many words once ending in ‑our (for example, chancellour and governour ) reverted to ‑or . A few words of
19511-513: The equator, gravity is stronger there. Using geometric calculations, he gave a concrete argument as to the hypothetical ellipsoid shape of the Earth. The goal of Principia was not to provide exact answers for natural phenomena, but to theorise potential solutions to these unresolved factors in science. Newton pushed for scientists to look further into the unexplained variables. Two prominent researchers whom he inspired were Alexis Clairaut and Pierre Louis Maupertuis . They both sought to prove
19690-423: The equilibrium position. When released, the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum, and also to a slight degree on its weight distribution (the moment of inertia about its own center of mass) and
19869-550: The error is explained in the article on measurement uncertainty . Practical realisation of the metre is subject to uncertainties in characterising the medium, to various uncertainties of interferometry, and to uncertainties in measuring the frequency of the source. A commonly used medium is air, and the National Institute of Standards and Technology (NIST) has set up an online calculator to convert wavelengths in vacuum to wavelengths in air. As described by NIST, in air,
20048-406: The etymology was not clear, and therefore some scholars advocated ‑or only and others ‑our only. Webster's 1828 dictionary had only -or and is given much of the credit for the adoption of this form in the United States. By contrast, Johnson's 1755 (pre-U.S. independence and establishment) dictionary used -our for all words still so spelled in Britain (like colour ), but also for words where
20227-425: 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 was later explained by clearance in
20406-514: 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 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
20585-412: 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 3269 thousand toises . 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
20764-443: The flattening of the Earth was 1 / 330 . A modern estimate is 1 / 298.25642 . In 1790, one year before the metre was ultimately based on a quadrant of the Earth, Talleyrand proposed that the metre be the length of the seconds pendulum at a latitude of 45°. This option, with one-third of this length defining the foot , was also considered by Thomas Jefferson and others for redefining
20943-404: The geodetic results in proving that the Earth is flattened at the poles. The acceleration of a body near the surface of the Earth, which is measured with the seconds pendulum, is due to the combined effects of local gravity and centrifugal acceleration . The gravity diminishes with the distance from the center of the Earth while the centrifugal force augments with the distance from the axis of
21122-462: 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 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
21301-685: The influence of the American labor movement and King O'Malley . On top of that, some place names in South Australia such as Victor Harbor , Franklin Harbor or Outer Harbor are usually spelled with the -or spellings. Aside from that, -our is now almost universal in Australia but the -or endings remain a minority variant. New Zealand English , while sharing some words and syntax with Australian English , follows British usage. In British English, some words from French, Latin or Greek end with
21480-400: 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 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
21659-412: The length of a mean solar day is nearly constant, unlike that of an apparent solar day. An apparent solar day can be 20 seconds shorter or 30 seconds longer than a mean solar day. Long or short days occur in succession, so the difference builds up until mean time is ahead of apparent time by about 14 minutes near February 6 and behind apparent time by about 16 minutes near November 3. The equation of time
21838-451: The length of the string will be approximately 993.6 millimetres, i.e. less than a centimetre short of one metre everywhere on Earth. This is because the value of g , expressed in m/s , is very close to π . The pendulum clock was invented in 1656 by Dutch scientist and inventor Christiaan Huygens , and patented the following year. Huygens contracted the construction of his clock designs to clockmaker Salomon Coster , who actually built
22017-601: 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 the temperature. A French scientific instrument maker, Jean Nicolas Fortin , had made three direct copies of
22196-447: The meantime, the commission of the French Academy of Sciences calculated a provisional value from older surveys of 443.44 lignes. This value was set by legislation on 7 April 1795. In 1799, a commission including Johan Georg Tralles , Jean Henri van Swinden , Adrien-Marie Legendre and Jean-Baptiste Delambre calculated the distance from Dunkirk to Barcelona using the data of the triangulation between these two towns and determined
22375-534: 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 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
22554-686: 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. The task of surveying the Paris meridian arc 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 French 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
22733-461: The melting point of ice. 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 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,
22912-404: 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 vertical deflections was minimized in proportion to the length of the meridian arcs: the longer the meridian arcs, the more precise the image of the Earth ellipsoid would be. After Struve Geodetic Arc measurement, it was resolved in
23091-417: The mid-18th century precision pendulum clocks achieved accuracies of a few seconds per week. At the time the second was defined as a fraction of the Earth's rotation time or mean solar day and determined by clocks whose precision was checked by astronomical observations. Solar time is a calculation of the passage of time based on the position of the Sun in the sky . The fundamental unit of solar time
23270-405: The minute hand, previously rare, to be added to clock faces beginning around 1690. The 18th- and 19th-century wave of horological innovation that followed the invention of the pendulum brought many improvements to pendulum clocks. The deadbeat escapement invented in 1675 by Richard Towneley and popularised by George Graham around 1715 in his precision "regulator" clocks gradually replaced
23449-414: The nature of the suffix used. The u is kept before English suffixes that are freely attachable to English words (for example in humourless , neighbourhood , and savoury ) and suffixes of Greek or Latin origin that have been adopted into English (for example in behaviourism , favourite , and honourable ). However, before Latin suffixes that are not freely attachable to English words,
23628-399: The number of wavelengths of laser light of one of the standard types that fit into the length, and converting the selected unit of wavelength to metres. Three major factors limit the accuracy attainable with laser interferometers for a length measurement: Of these, the last is peculiar to the interferometer itself. The conversion of a length in wavelengths to a length in metres is based upon
23807-455: 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. Improvements in
23986-412: The only problems the surveyors had to face in the convulsed period of the aftermath of the French 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 of the French Academy of Sciences calculated
24165-475: The pendulum inaccurate, causing its period , and thus the rate of the clock, to vary with unavoidable variations in the driving force provided by the movement . Clockmakers' realisation that only pendulums with small swings of a few degrees are isochronous motivated the invention of the anchor escapement around 1670, which reduced the pendulum's swing to 4–6°. The anchor became the standard escapement used in pendulum clocks. In addition to increased accuracy,
24344-464: The pendulum, the first harmonic oscillator used in timekeeping, increased the accuracy of clocks enormously, from about 15 minutes per day to 15 seconds per day leading to their rapid spread as existing ' verge and foliot ' clocks were retrofitted with pendulums. These early clocks, due to their verge escapements , had wide pendulum swings of 80–100°. In his 1673 analysis of pendulums, Horologium Oscillatorium , Huygens showed that wide swings made
24523-559: 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 Spanish-French geodetic mission and a value of 1 / 334 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
24702-539: The relation American and British English spelling differences#-re, -er A "British standard" began to emerge following the 1755 publication of Samuel Johnson 's A Dictionary of the English Language , and an "American standard" started following the work of Noah Webster and, in particular, his An American Dictionary of the English Language , first published in 1828. Webster's efforts at spelling reform were effective in his native country, resulting in certain well-known patterns of spelling differences between
24881-437: The results of the Spanish-French geodetic mission and found a value of 1/334 for the Earth's flattening , and they then extrapolated from their measurement of the Paris meridian arc between Dunkirk and Barcelona the distance from the North Pole to the Equator which was 5 130 740 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
25060-420: The same length, confirming an hypothesis of Jean Le Rond d'Alembert . He also proposed an ellipsoid with three unequal axes. In 1860, Elie Ritter, a mathematician from Geneva , using Schubert's data computed that the Earth ellipsoid could rather be a spheroid of revolution accordingly to Adrien-Marie Legendre 's model. However, the following year, resuming his calculation on the basis of all the data available at
25239-454: The scientific means necessary to redefine the units of the metric system according to the progress of sciences. The Metre Convention ( Convention du Mètre ) of 1875 mandated the establishment of a permanent International Bureau of Weights and Measures (BIPM: Bureau International des Poids et Mesures ) to be located in Sèvres , France. This new organisation was to construct and preserve
25418-683: 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 preliminary proposal made in Neuchâtel the precedent year, the General Conference recommended the adoption of the metre in replacement of
25597-413: The seconds pendulum's length in his Principia Mathematica (1687) in which he outlined his theory and calculations on the shape of the Earth. Newton theorised correctly that the Earth was not precisely a sphere but had an oblate ellipsoidal shape, slightly flattened at the poles due to the centrifugal force of its rotation. Since the surface of the Earth is closer to its centre at the poles than at
25776-526: The shape that he did, but he did not support it in Principia . Clairaut's article did not provide a valid equation to back up his argument. This created much controversy in the scientific community. It was not until Clairaut wrote Théorie de la figure de la terre in 1743 that a proper answer was provided. In it, he promulgated what is more formally known today as Clairaut's theorem . By applying Clairaut's theorem, Laplace found from 15 gravity values that
25955-475: The simplified form palestra is described by Merriam-Webster as "chiefly Brit[ish]." This is a reverse of the typical rule, where British spelling uses the ae / oe and American spelling simply uses e . Words that can be spelled either way in British English include cham a eleon , encyclop a edia , hom o eopathy , medi a eval (a minor variant in both AmE and BrE ), f o etid and f o etus . The spellings f o etus and f o etal are Britishisms based on
26134-406: The size of the metre significantly – today Earth's polar circumference measures 40 007 .863 km , a change of about 200 parts per million from the original value of exactly 40 000 km , which also includes improvements in the accuracy of measuring the circumference. Metre is the standard spelling of the metric unit for length in nearly all English-speaking nations, the exceptions being
26313-410: The sounds became monophthongs , and later applied to words not of Greek origin, in both Latin (for example, cœli ) and French (for example, œuvre ). In English, which has adopted words from all three languages, it is now usual to replace Æ/æ with Ae/ae and Œ/œ with Oe/oe . In many words, the digraph has been reduced to a lone e in all varieties of English: for example, o economics , pr
26492-695: The spelling "is often seen as such". The -ize form is known as Oxford spelling and is used in publications of the Oxford University Press, most notably the Oxford English Dictionary , and of other academic publishers such as Nature , the Biochemical Journal and The Times Literary Supplement . It can be identified using the IETF language tag en-GB-oxendict (or, historically, by en-GB-oed ). In Ireland, India, Australia, and New Zealand -ise spellings strongly prevail:
26671-608: The spellings with just e are increasingly used. Manoeuvre is the only spelling in Australia, and the most common one in Canada, where maneuver and manoeuver are also sometimes found. The -ize spelling is often incorrectly seen in Britain as an Americanism. It has been in use since the 15th century, predating the -ise spelling by over a century. The verb-forming suffix -ize comes directly from Ancient Greek -ίζειν ( -ízein ) or Late Latin -izāre , while -ise comes via French -iser . The Oxford English Dictionary ( OED ) recommends -ize and lists
26850-432: The standard both for the unit of length and for the second. These two quantities could then be used to define the unit of mass. About the unit of length he wrote: In the present state of science the most universal standard of length which we could assume would be the wave length in vacuum of a particular kind of light, emitted by some widely diffused substance such as sodium, which has well-defined lines in its spectrum. Such
27029-504: The standard unit of length. In 1671 Jean Picard measured this length at the Paris observatory . He found the value of 440.5 lignes of the Toise of Châtelet which had been recently renewed. He proposed a universal toise (French: Toise universelle ) which was twice the length of the seconds pendulum. However, it was soon discovered that the length of a seconds pendulum varies from place to place: French astronomer Jean Richer had measured
27208-478: The structure of space. Einstein's theory of gravity 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 the Sun during an eclipse in 1919. In 1873, James Clerk Maxwell suggested that light emitted by an element be used as
27387-448: 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 the 18th century, in addition of 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
27566-456: 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 was chosen for this purpose, as it had served as a model for the construction of the Egyptian standard. In addition,
27745-463: The term metro cattolico 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. Christiaan Huygens found out the centrifugal force which explained variations of gravitational acceleration depending on latitude. He also mathematically formulated the link between the length of the simple pendulum and gravitational acceleration. According to Alexis Clairaut ,
27924-438: The theoretical definition of the metre had been inaccessible and misleading at the time of Delambre and Mechain arc measurement, as the geoid is a ball, which on the whole can be assimilated to an oblate spheroid , 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, Friedrich von Schubert demonstrated that several meridians had not
28103-406: 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 vertical deflections , in particular the latitude of Montjuïc in the French meridian arc which determination had also been affected in a lesser proportion by systematic errors of the repeating circle . The definition of the length of a metre in
28282-549: 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 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
28461-436: The uncertainties in characterising the medium are dominated by errors in measuring temperature and pressure. Errors in the theoretical formulas used are secondary. By implementing a refractive index correction such as this, an approximate realisation of the metre can be implemented in air, for example, using the formulation of the metre as 1 579 800 .762 042 (33) wavelengths of helium–neon laser light in vacuum, and converting
28640-569: The uncertainty involved in the direct comparison of wavelengths, because interferometer errors were eliminated. To further facilitate reproducibility from lab to lab, the 17th CGPM also made the iodine-stabilised helium–neon laser "a recommended radiation" for realising the metre. For the purpose of delineating the metre, the BIPM currently considers the HeNe laser wavelength, λ HeNe , to be 632.991 212 58 nm with an estimated relative standard uncertainty ( U ) of 2.1 × 10 . This uncertainty
28819-427: The validity of Newton's theory on the shape of the Earth. In order to do so, they went on an expedition to Lapland in an attempt to accurately measure the meridian arc . From such measurements they could calculate the eccentricity of the Earth, its degree of departure from a perfect sphere. Clairaut confirmed that Newton's theory that the Earth was ellipsoidal was correct, but his calculations were in error; he wrote
28998-412: The vowel is unreduced in pronunciation (e.g., devour , contour , flour , hour , paramour , tour , troubadour , and velour ), the spelling is uniform everywhere. Most words of this kind came from Latin, where the ending was spelled ‑or . They were first adopted into English from early Old French , and the ending was spelled ‑our , ‑or or ‑ur . After the Norman conquest of England ,
29177-435: The wavelengths in vacuum to wavelengths in air. Air is only one possible medium to use in a realisation of the metre, and any partial vacuum can be used, or some inert atmosphere like helium gas, provided the appropriate corrections for refractive index are implemented. The metre is defined as the path length travelled by light in a given time, and practical laboratory length measurements in metres are determined by counting
29356-624: The word fiord (instead of fjord ) . There is an increasing use of macrons in words that originated in Māori and an unambiguous preference for -ise endings (see below). Most words ending in an unstressed ‑our in British English (e.g., behaviour , colour , favour , flavour , harbour , honour , humour , labour , neighbour , rumour , splendour ) end in ‑or in American English ( behavior , color , favor , flavor , harbor , honor , humor , labor , neighbor , rumor , splendor ). Wherever
29535-455: The word metre (for the French unit mètre ) in English began at least as early as 1797. Galileo discovered gravitational acceleration to explain 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 the length of the pendulum. Kepler's laws of planetary motion served both to the discovery of Newton's law of universal gravitation and to
29714-428: The word pallor . As a general noun, rigour / ˈ r ɪ ɡ ər / has a u in the UK; the medical term rigor (sometimes / ˈ r aɪ ɡ ər / ) does not, such as in rigor mortis , which is Latin. Derivations of rigour / rigor such as rigorous , however, are typically spelled without a u , even in the UK. Words with the ending -irior , -erior or similar are spelled thus everywhere. The word armour
29893-499: The yard in the United States shortly after gaining independence from the British Crown. Instead of the seconds pendulum method, the commission of the French Academy of Sciences – whose members included 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
30072-476: Was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length . From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in vacuum in 1 / 299 792 458 of a second . After the 2019 revision of the SI , this definition was rephrased to include the definition of a second in terms of the caesium frequency Δ ν Cs . This series of amendments did not alter
30251-520: 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,
30430-567: 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 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
30609-755: Was mitigated by that of neutral states. While the German astronomer Wilhelm Julius Foerster , director of the Berlin Observatory and director of the German Weights and Measures Service boycotted the Permanent Committee of the International Metre Commission, along with the Russian and Austrian representatives, in order to promote the foundation of a permanent International Bureau of Weights and Measures ,
30788-471: 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
30967-666: Was not until the mid-1990s that Canadian-based dictionaries became increasingly common.) Worldwide, -ize endings prevail in scientific writing and are commonly used by many international organizations, such as United Nations Organizations (such as the World Health Organization and the International Civil Aviation Organization ) and the International Organization for Standardization (but not by
31146-428: Was once somewhat common in American usage but has disappeared except in some brand names such as Under Armour . The agent suffix -or ( separator , elevator , translator , animator , etc.) is spelled thus both in American and British English. Commonwealth countries normally follow British usage. Canadian English most commonly uses the -our ending and -our- in derivatives and inflected forms. However, owing to
31325-457: Was particularly worrying, because when the primary Imperial yard 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 Ferdinand Rudolph Hassler 's use of the metre and
31504-929: Was published. Following this, -re became the most common usage in Britain. In the United States, following the publication of Webster's Dictionary in the early 19th century, American English became more standardized, exclusively using the -er spelling. In addition, spelling of some words have been changed from -re to -er in both varieties. These include September , October , November , December , amber, blister , cadaver , chamber , chapter , charter , cider , coffer , coriander , cover , cucumber , cylinder , diaper , disaster , enter , fever , filter , gender , leper , letter , lobster , master , member , meter (measuring instrument) , minister , monster , murder , number , offer , order , oyster , powder , proper , render , semester , sequester , sinister , sober , surrender , tender , and tiger . Words using
31683-465: Was the first to tie experimentally the metre to the wave length of a spectral line. According to him the standard length might be compared with that of a wave of light identified by a line in the solar spectrum . Albert Michelson soon took up the idea and improved it. In 1893, the standard metre was first measured with an interferometer by Albert A. Michelson , the inventor of the device and an advocate of using some particular wavelength of light as
31862-441: Was ultimately decided that the metre would be based on the Earth quadrant (a quarter of the Earth's circumference through its poles), Talleyrand proposed that the metre be the length of the seconds pendulum at a latitude of 45°. 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
32041-437: Was very influential in popularizing certain spellings in the United States, but he did not originate them. Rather [...] he chose already existing options such as center, color and check for the simplicity, analogy or etymology". William Shakespeare 's first folios , for example, used spellings such as center and color as much as centre and colour . Webster did attempt to introduce some reformed spellings, as did
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