Alexander Ross Clarke FRS FRSE (1828–1914) was a British geodesist, primarily remembered for his calculation of the Principal Triangulation of Britain (1858), the calculation of the Figure of the Earth (1858, 1860, 1866, 1880) and one of the most important text books of Geodesy (1880). He was a military officer of the Royal Engineers employed on the Ordnance Survey, attaining the rank of colonel.
Biographical details Sources The basic sources of material on Clarke are the two articles by Charles Close, one of the Directors of the Ordnance Survey. The first was an article for the Royal Engineers Journal and the second, a revised and expanded version, appeared in the Empire Survey ReviewThe Empire Survey Review changed its name to Survey Review in 1963.. Although Close was almost thirty years younger than Clarke, and joined the Ordnance Survey only after Clarke's retirement, they knew each other well and they collaborated on the article Map for the eleventh edition of Encyclopædia Britannica. Much of Close's material is incorporated in the web page REubiqueThe motto of the Royal Engineers is Ubique or everywhere. (de Santis 2002) along with details of his military career and further information communicated by one of Clarke's living descendants. Other sources of information are to be found in the Times of LondonSee , , , . Note that the digital archive is freely accessible in most libraries in Britain and America. and obituaries in several learned societies.The Royal Society obituary and the Nature obituary are most comprehensive. Two recent histories of the Ordnance Survey include information on Clarke: Owen and Pilbeam, page 55 (true) or 64 (pdf) and Seymour. pp. 139—146 (true) or pp. 153—160 (pdf).
Family background and education 1828–1850 Clarke was born in Reading, Berkshire, England on 16 December 1828. His Scottish father, David Ross Clarke, had travelled to Jamaica as a young merchant and there he married Elizabeth (Eliza) Ann Hall, the daughter of Colonel Charles William Hall and Isabella Ann Ford, on 8 March 1827 in Kingston.Information on Clarke's parents is taken from a Turnbull family website. The relevant pages are found under the entries for Clarke and a document relating to the Hall family. They came to England for the birth of Alexander but they must have returned to Jamaica very soon afterwards for Alexander would later regale his own children with stories of his childhood experiences in the colony.
The parents, David and Eliza, were back in England by 1834The Clarke Family Bible shows that David Clarke's eldest daughter was born at Canterbury in 1834 but they soon moved up to David's family home at EribollDavid Clarke was born on 28 February 1800 at Keddale in the parish of Durness. Record At some later date the family moved to Eriboll in the same parish. in the far north of Scotland. The school teaching there was primitive but effective. repeats an anecdote told by Alexander's younger brother: "I do not know what schooling he had in those young days, but I remember his telling me of a dominieDominie is an old Scottish term for teacher. putting him under his desk and kicking him from time to time, also how tawsThe tawse was the standard implement of school punishment in Scotland. were used. Anyway he learned Latin and mathematics." Close adds that "The mathematics that was thus kicked into him determined his career in after life."
David Clarke and his family moved to London, before 1846, and eventually settled at 35 Devonshire Place, where he died in 1861. His wife, Eliza Ann, died in 1887. It was from this London address that Alexander Clarke, at the age of seventeen in 1846, applied to the Royal Military Academy, Woolwich as a Gentleman Cadet.For an account of Gentleman Cadets see The History of RMA Sandhurst. Clarke was very unprepared for the entrance examination, having left a space of only three weeks for revision, and he was placed bottom of the list of candidates. At Woolwich he would undergo basic military training and formal teaching in subjects such as mathematics and engineering. Clarke excelled at his studies and he passed out first, with "the reputation of being an exceptionally capable young man" . He was commissioned as a second lieutenant in the Royal Engineers on 1 October 1847.For more on the Royal Military Academy at Woolwich see the RE website which includes a page for the class of 1847
After his commissioning, Clarke attended the Young Officers Course at the Royal School of Military Engineering at Chatham and there he would have studied surveying as well as military engineering. He was promoted to the rank of Lieutenant on 11 July 1849 at the end of that course.
Ordnance Survey 1850–1881 In 1849, during the last months of his time at Chatham, Clarke decided to try for the Ordnance Survey and he made an indirect approach to the Superintendent, Colonel Hall, through the good offices of Colonel Reid, his former professor at the Royal Military Academy . Hall had no funds to employ Clarke that year but he recruited him the following year when the government approved funding for the preparation of the final report on the Principal Triangulation of Great Britain. This was an opportune moment, for the Survey had recently lost some of its senior staff and, at the same time, Hall had banished Captain William Yolland, the most able member of the Survey, to its remotest office in Enniskillen.For an account of the disastrous relationship between Hall and Yolland see pp. 44—46 (52—54 in pdf)
Before Clarke could make progress on the calculation of the triangulation, the War Office intervened and abruptly dispatched him to military service in Canada. The nature of the posting is not recorded but it had one happy outcome. Clarke met, and married,The wedding took place in Montreal on 1 November 1853: see or PDF transcription Frances Maria, youngest daughter of Colonel Matthew C. Dixon, his commanding officer.
Superintendent Hall retired in 1854 and Yolland, the most competent member of the Survey, was passed over in favour of Colonel Henry James. Yolland resigned immediately and Clarke was the only qualified candidate for the analysis of the triangulation. (James was not a mathematician.) The magnitude of this task is discussed below. The report was accomplished by 1858, an exceedingly short period of time. His endeavour was rewarded by his military promotion to 2nd Captain in 1855 and by being appointed head of the Trigonometrical and Levelling Departments of the Ordnance Survey in 1856.
Clarke worked intensely on a number of major projects (below) during the 27 years to 1881, all of which were described in voluminous reports. Clarke appears to have got on well enough with Superintendent James despite James's habit of having his name well to the forefront on these reports.For a review of Hall's tenure at the Survey see p53 (p62 in pdf). The total experience of these years was distilled in Clarke's famous textbook, Geodesy.See . claims that Clarke invented the term Geodesy. This is untrue for the OED claims that the word is first found with its modern meaning in the writing of John Dee,1570.
Clarke's contribution to the Survey greatly enhanced its reputation. He himself was acknowledged as one of greatest geodesists in the world and he was honoured with fellowships at the Royal Society of London (1862) and the Philosophical Society of Cambridge (1871). He was also elected a Corresponding Member of the Russian Imperial Academy of Sciences (1868).Clarke had cooperated closely with Struve on geodetic matters. He was made a Companion of the Most Honourable Order of the Bath in 1870.Order of the Bath reported in His army promotions were to Captain (1861), Major of Army Rank (1871), Major of Regimental Rank (1872), Lieutenant Colonel (1872) and Colonel (1877). (See de Santis 2002).
The Clarke family lived in Southampton from 1854 to 1881, the last twenty years in a fashionable Georgian property at 21, Carlton Crescent.See the article by and also note the listing at English Heritage . The family was large, nine daughters, and four boys, one of whom died young. During the time of intense activity with the Survey, Clarke preferred to work at home with this large family around him. . Two of the girls and the three boys married. One son, Eric Manley Clarke, later was the first teacher in mathematics at the Lincoln Agricultural College (now Lincoln University) in Lincoln, New Zealand.
Retirement and legacy 1881–1914
Superintendent James retired in 1875 and he was succeeded by his deputy, Colonel John Cameron. He died suddenly in 1878 and after his death Clarke was made acting head of the Survey until the appointment of Colonel Anthony C. Cooke.See the list of Directors-General It was surprising that Clarke himself was not appointed. Three years later the War Office intervened in his career once again; "an official of a well-known type woke up to the fact that he had been at a home station (i.e. the Survey at Southampton) for twenty-seven years, and he was ordered to go to Mauritius" . Clarke, a man of some-what hasty temper (Close), strongly resented this summary order which involved such a complete break with his life's work and he promptly sent in his resignation from the Army.Clarke's friend and fellow RE, Colonel George Gordon, later General Gordon, tried to persuade Clarke to withdraw his resignation but he refused and Gordon himself took the posting to Mauritius. Despite protestations to the War Office from the scientific establishment, Clarke's resignation was allowed to stand. "Clarke's retirement was a veritable disaster for the Survey, and his departure lowered the whole tone and scientific status of the department for many a long year." .
From 1881 Clarke's involvement with geodesy becomes more and more tenuous. In October 1883 he and Airy were the British delegates at the International Geodetic Conference in Rome, and in 1884 he represented Britain at the International Meridian Conference. Thereafter he published no further work on the subject apart from his revision, with Helmert, of his Encyclopædia Britannica articles. His fame was not diminished in any way: he was made an honorary Fellow of both the Royal Society of Edinburgh (1892) and the Royal Astronomical Society. His most prestigious award was the Royal Medal of the Royal Society of London in 1887.Royal medal citation: . The text of the citation is as follows: "The medal which, in accordance with the usual rule has been devoted to mathematics and physics, has this year been awarded to Colonel A. Clarke for his comparison of standards of length, and determination of the figure of the earth. Col. Clarke was for some 25 years the scientific and mathematical adviser for the Ordnance Survey, and while acting in that capacity he became known to the whole scientific world as possessing unique knowledge and power in dealing with the complex questions which arise in the science of geodesy. His laborious comparison of the standards of length, carried out under General Sir Henry James, R.E., are universally regarded as models of scientific precision. His determination of the ellipticity and dimensions of the earth from the great arcs of meridian and longitude involved a very high mathematical ability and an enormous amount of labour. The conclusion at which he arrived removed an apparent discrepancy between the results of pendulum experiments and those derived from geodesy, and is generally accepted as the best approximation hitherto attained as to the figure of the earth."