William Jones, FRS (16751 July 1749) was a Welsh mathematician best known for his use of the symbol (the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

letter '' Pi'') to represent the ratio of the circumference of a circle to its diameter. He was a close friend of Sir

Isaac Newton Sir Isaac Newton () was an English polymath active as a mathematician, physicist, astronomer, alchemist, theologian, and author. Newton was a key figure in the Scientific Revolution and the Age of Enlightenment, Enlightenment that followed ...

and Sir

Edmund Halley Edmond (or Edmund) Halley (; – ) was an English astronomer, mathematician and physicist. He was the second Astronomer Royal in Britain, succeeding John Flamsteed in 1720. From an observatory he constructed on Saint Helena in 1676–77, H ...

. In November 1711, Jones became a

fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

, and later served as the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

's vice-president.

Early life

William Jones was born as the son of Siôn Siôr (John George Jones) and Elizabeth Rowland in the parish of

Llanfihangel Tre'r Beirdd Llanfihangel (English: ''St Michael's Church'') can refer to the following places in Wales: *Llanfihangel Aberbythych, Carmarthenshire *Llanfihangel-ar-Arth, Carmarthenshire *Llanfihangel Bachellaeth, Gwynedd *Llanfihangel-clogwyn-gofan, the Welsh ...

, about west of Benllech on the

Isle of Anglesey Anglesey ( ; ) is an island off the north-west coast of Wales. It forms the bulk of the Principal areas of Wales, county known as the Isle of Anglesey, which also includes Holy Island, Anglesey, Holy Island () and some islets and Skerry, sker ...

in Wales. He attended a

charity school Charity schools, sometimes called blue coat schools, or simply the Blue School, were significant in the history of education in England. They were built and maintained in various parishes by the voluntary contributions of the inhabitants to ...

at Llanfechell, also on the Isle of Anglesey, where his mathematical talents were spotted by the local landowner Lord Bulkeley, who arranged for him to work in a merchant's counting-house in

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

. His main patrons were the Bulkeley family of north

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

, and later the Earl of Macclesfield.

Early mathematical career

Jones initially served at sea, teaching mathematics on board Navy ships between 1695 and 1702, where he became very interested in navigation and published ''A New Compendium of the Whole Art of Navigation'' in 1702, dedicated to a benefactor John Harris. In this work he applied mathematics to navigation, studying methods of calculating position at sea. After his voyages were over he became a mathematics teacher in London, both in coffee houses and as a private tutor to George Parker, the son of the future Earl of Macclesfield, and also the future Baron Hardwicke.

Later career

Jones published ''Synopsis Palmariorum Matheseos'' in 1706, a work which was intended for beginners and which included theorems on

differential calculus In mathematics, differential calculus is a subfield of calculus that studies the rates at which quantities change. It is one of the two traditional divisions of calculus, the other being integral calculus—the study of the area beneath a curve. ...

and

infinite series In mathematics, a series is, roughly speaking, an addition of infinitely many terms, one after the other. The study of series is a major part of calculus and its generalization, mathematical analysis. Series are used in most areas of mathemati ...

. This used for the ratio of circumference to diameter, following earlier abbreviations for the Greek word ''periphery'' (περιφέρεια) by

William Oughtred William Oughtred (5 March 1574 – 30 June 1660), also Owtred, Uhtred, etc., was an English mathematician and Anglican clergyman.'Oughtred (William)', in P. Bayle, translated and revised by J.P. Bernard, T. Birch and J. Lockman, ''A General ...

and others. His 1711 work ''Analysis per quantitatum series, fluxiones ac differentias'' introduced the dot notation for differentiation in calculus. He was noticed and befriended by two of Britain's foremost mathematicians –

and

Sir Isaac Newton Sir Isaac Newton () was an English polymath active as a mathematician, physicist, astronomer, alchemist, theologian, and author. Newton was a key figure in the Scientific Revolution and the Enlightenment that followed. His book (''Mathe ...

– and was elected a fellow of the Royal Society in 1711. He later became the editor and publisher of many of Newton's manuscripts and built up an extraordinary library that was one of the greatest collections of books on science and mathematics ever known, and only recently fully dispersed. Jones' Last Will and Testament left his library, along with his gold watch, to Earl of Macclesfield in acknowledgement of his support.

Personal life

He married twice, firstly the widow of his counting-house employer, whose property he inherited on her death, and secondly, in 1731, Mary, the 22-year-old daughter of cabinet-maker George Nix, with whom he had two surviving children. His son, also named William Jones and born in 1746, was a renowned

philologist Philology () is the study of language in oral and written historical sources. It is the intersection of textual criticism, literary criticism, history, and linguistics with strong ties to etymology. Philology is also defined as the study of ...

who established links between Latin, Greek and Sanskrit, leading to the concept of the

Indo-European language The Indo-European languages are a language family native to the northern Indian subcontinent, most of Europe, and the Iranian plateau with additional native branches found in regions such as Sri Lanka, the Maldives, parts of Central Asia ( ...

group.

References

External links

William Jones
and other important Welsh mathematicians
William Jones and his Circle: The Man who invented PiPi Day 2015: meet the man who invented π
{{DEFAULTSORT:Jones, William 1675 births 1749 deaths People from Anglesey 17th-century English mathematicians 18th-century British mathematicians Fellows of the Royal Society 17th-century Welsh scientists 18th-century Welsh scientists 18th-century Welsh mathematicians Pi-related people