Alexander Ross Clarke in 1861.

Alexander Ross Clarke (1828-1914) was a British geodesist, primarily remembered for his work defining different reference ellipsoids approximating the shape of the geoid. 1828 was a leap year starting on Tuesday (see link for calendar). ... 1914 (MCMXIV) was a common year starting on Thursday. ... In geodesy, a reference ellipsoid is a mathematically-defined surface that approximates the geoid, the true figure of the Earth or other planetary body. ... The GOCE project will measure high-accuracy gravity gradients and provide an accurate geoid model based on the Earths gravity field. ...

Clarke was born on December 16, 1828 in Reading, Berkshire, England. He spent his childhood in the British colony of Jamaica, until his family returned to England. Reading is a town and unitary authority (the Borough of Reading) in the English county of Berkshire. ... Motto: (French for God and my right) Anthem: Multiple unofficial anthems Capital London Largest city London Official language(s) English (de facto) Government Constitutional monarchy  - Queen Queen Elizabeth II  - Prime Minister Tony Blair MP Unification    - by Athelstan AD 927  Area    - Total 130,395 km² (1st in UK)   50,346 sq...

On October 1, 1847 he joined the British army and was assigned to the Royal Engineers. He got his training in Chatham, Kent, at the School of Military engineering. In 1850 he was transferred to the Ordnance Survey in Southampton. Chatham is an English town that developed around an important naval dockyard on the east bank of the River Medway in the county of Kent. ... Kent is a county in England, south-east of London. ... Image produced from the Ordnance Survey Get-a-map service. ... Southampton is a city and major port situated on the south coast of England. ...

From 1851 to 1854 Clark served in Canada, where he married Frances Dixon in 1853.

Clarke returned to England and served again with the Ordnance Survey in Southampton, where in 1856 he became director of the measurement department. In the year 1858 he published his first article on the history of land surveying in Great Britain. On June 5 1862 he was elected to the Royal Society. The premises of the Royal Society in London (first four properties only). ...

In 1866 he described a new reference ellipsoid, known as Clarke 1866 and still used today, particularly in English-language countries and areas. In his 1880 book Geodesy he described a different ellipsoid, known as Clarke 1880, which is used mainly in Africa. In geodesy, a reference ellipsoid is a mathematically-defined surface that approximates the geoid, the true figure of the Earth or other planetary body. ... The expression figure of the Earth has various meanings in geodesy according to the way it is used and the precision with which the Earths size and shape is to be defined. ... The expression figure of the Earth has various meanings in geodesy according to the way it is used and the precision with which the Earths size and shape is to be defined. ...

After he had served 27 years in England, he was formally obliged to serve overseas. Upon receiving notice of transfer, Clarke submitted his resignation. Soon after he withdrew from the Royal Society for financial reasons. The premises of the Royal Society in London (first four properties only). ...

In October 1883 Clarke was the British delegate at the geodetic conference in Rome, and in 1884 he represented Britain at the International Geodetic Conference.

From the Royal Society he received the gold medal, and was re-elected to membership and his dues were waived.

Alexander Ross Clarke died on 11 February 1914 in Strathmore, Reigate, Surrey. Strathmore, from the Scottish Gaelic for large valley, can refer to a number of places in Scotland, or places named by Scottish emigrants: // Scotland Several places in Scotland are known as Strathmore including: Strathmore, Angus and Perth & Kinross, where Glamis Castle can be found Strathmore, Sutherland, home of Rob Donn... Reigate is a historic market town in Surrey, England at the foot of the North Downs. ... Surrey is a county in southern England, part of the South East England region and one of the Home Counties. ...

Clarke and his wife had four sons and nine daughters.

References

• Colonel Sir Charles Close, K.B.E., C.B., C.M.G., F.R.S. "The Life and Work of Colonel Clarke." The Royal Engineers Journal Vol. XXXIX, No. 4 (December 1925), pp. 658-665.

External links

• Short biography of Alexander Clarke