John Playfair
Encyclopedia
Royal Society of Edinburgh
The Royal Society of Edinburgh is Scotland's national academy of science and letters. It is a registered charity, operating on a wholly independent and non-party-political basis and providing public benefit throughout Scotland...
, FRS (10 March 1748 – 20 July 1819) was a Scottish
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
scientist
Scientist
A scientist in a broad sense is one engaging in a systematic activity to acquire knowledge. In a more restricted sense, a scientist is an individual who uses the scientific method. The person may be an expert in one or more areas of science. This article focuses on the more restricted use of the word...
and mathematician
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
, and a professor of natural philosophy
Natural philosophy
Natural philosophy or the philosophy of nature , is a term applied to the study of nature and the physical universe that was dominant before the development of modern science...
at the University of Edinburgh
University of Edinburgh
The University of Edinburgh, founded in 1583, is a public research university located in Edinburgh, the capital of Scotland, and a UNESCO World Heritage Site. The university is deeply embedded in the fabric of the city, with many of the buildings in the historic Old Town belonging to the university...
. He is perhaps best known for his book Illustrations of the Huttonian Theory of the Earth (1802), which summarized the work of James Hutton
James Hutton
James Hutton was a Scottish physician, geologist, naturalist, chemical manufacturer and experimental agriculturalist. He is considered the father of modern geology...
. It was through this book that Hutton's principle of uniformitarianism
Uniformitarianism (science)
In the philosophy of naturalism, the uniformitarianism assumption is that the same natural laws and processes that operate in the universe now, have always operated in the universe in the past and apply everywhere in the universe. It has included the gradualistic concept that "the present is the...
, later taken up by Charles Lyell
Charles Lyell
Sir Charles Lyell, 1st Baronet, Kt FRS was a British lawyer and the foremost geologist of his day. He is best known as the author of Principles of Geology, which popularised James Hutton's concepts of uniformitarianism – the idea that the earth was shaped by slow-moving forces still in operation...
, first reached a wide audience. Playfair also is remembered for his proposal of an alternative to Euclid
Euclid
Euclid , fl. 300 BC, also known as Euclid of Alexandria, was a Greek mathematician, often referred to as the "Father of Geometry". He was active in Alexandria during the reign of Ptolemy I...
's parallel postulate.
Early life
Born at Benvie, AngusAngus
Angus is one of the 32 local government council areas of Scotland, a registration county and a lieutenancy area. The council area borders Aberdeenshire, Perth and Kinross and Dundee City...
, Scotland, where his father was parish
Parish
A parish is a territorial unit historically under the pastoral care and clerical jurisdiction of one parish priest, who might be assisted in his pastoral duties by a curate or curates - also priests but not the parish priest - from a more or less central parish church with its associated organization...
minister
Minister of religion
In Christian churches, a minister is someone who is authorized by a church or religious organization to perform functions such as teaching of beliefs; leading services such as weddings, baptisms or funerals; or otherwise providing spiritual guidance to the community...
, Playfair was educated at home until the age of fourteen, when he entered the University of St Andrews
University of St Andrews
The University of St Andrews, informally referred to as "St Andrews", is the oldest university in Scotland and the third oldest in the English-speaking world after Oxford and Cambridge. The university is situated in the town of St Andrews, Fife, on the east coast of Scotland. It was founded between...
. In 1766, when only eighteen, he was a candidate for the chair of mathematics in Marischal College
Marischal College
Marischal College is a building and former university in the centre of the city of Aberdeen in north-east Scotland. The building is owned by the University of Aberdeen and used for ceremonial events...
(now part of the University of Aberdeen
University of Aberdeen
The University of Aberdeen, an ancient university founded in 1495, in Aberdeen, Scotland, is a British university. It is the third oldest university in Scotland, and the fifth oldest in the United Kingdom and wider English-speaking world...
), and, although he was unsuccessful, his claims were admitted to be high.
Six years later he applied for the chair of natural philosophy in his own university, but again without success, and in 1773 he was offered and accepted the benefice
Benefice
A benefice is a reward received in exchange for services rendered and as a retainer for future services. The term is now almost obsolete.-Church of England:...
of the united parish
Parish
A parish is a territorial unit historically under the pastoral care and clerical jurisdiction of one parish priest, who might be assisted in his pastoral duties by a curate or curates - also priests but not the parish priest - from a more or less central parish church with its associated organization...
es of Liff
Liff, Scotland
Liff is a small hamlet northwest of Dundee in Angus, Scotland.It is the site of Royal Dundee Liff Hospital, a large psychiatric institution situated in the grounds of an expansive estate. The hospital is the successor to the Dundee Lunatic Asylum which, in 1882, moved out of the town of Dundee to...
and Benvie, vacant by the death of his father. Playfair continued, however, his mathematical and physical studies, and in 1782 he resigned his charge in order to become the tutor of Ferguson of Raith. By this arrangement, Playfair was able to be frequently in Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
and to cultivate the literary
Scottish literature
Scottish literature is literature written in Scotland or by Scottish writers. It includes literature written in English, Scottish Gaelic, Scots, Brythonic, French, Latin and any other language in which a piece of literature was ever written within the boundaries of modern Scotland.The earliest...
and scientific society for which it was at that time specially distinguished. In particular, he attended the natural history course of John Walker
John Walker (naturalist)
John Walker was a Scottish minister and natural historian. He was Professor of Natural History at the University of Edinburgh from 1779 to 1803....
. Through Nevil Maskelyne
Nevil Maskelyne
The Reverend Dr Nevil Maskelyne FRS was the fifth English Astronomer Royal. He held the office from 1765 to 1811.-Biography:...
, whose acquaintance he had first made in the course of the celebrated Schiehallion experiment
Schiehallion experiment
The Schiehallion experiment was an 18th-century experiment to determine the mean density of the Earth. Funded by a grant from the Royal Society, it was conducted in the summer of 1774 around the Scottish mountain of Schiehallion, Perthshire. The experiment involved measuring the tiny deflection of...
s in 1774, he also gained access to the scientific circles of London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. In 1785 when Dugald Stewart
Dugald Stewart
Dugald Stewart was a Scottish Enlightenment philosopher and mathematician. His father, Matthew Stewart , was professor of mathematics in the University of Edinburgh .-Life and works:...
succeeded Ferguson in the Edinburgh chair of moral philosophy, Playfair succeeded the former in that of mathematics.
Mature work
Playfair's axiom
Playfair's axiom is a geometrical axiom, intended to replace the fifth postulate of Euclides :Given a line and a point not on it, at most one parallel to the given line can be drawn through the point....
; though the axiom bears Playfair's name, he did not create it, but credited others, in particular William Ludlam (1718 - 1788), with the prior use of it.
In 1802, Playfair published his celebrated volume entitled Illustrations of the Huttonian Theory of the Earth. The influence exerted by James Hutton
James Hutton
James Hutton was a Scottish physician, geologist, naturalist, chemical manufacturer and experimental agriculturalist. He is considered the father of modern geology...
on the development of geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
is thought to be largely due to its publication. In 1805 Playfair exchanged the chair of mathematics for that of natural philosophy in succession to John Robison
John Robison (physicist)
John Robison FRSE was a Scottish physicist and mathematician. He was a professor of philosophy at the University of Edinburgh....
, whom also he succeeded as general secretary
General secretary
-International intergovernmental organizations:-International nongovernmental organizations:-Sports governing bodies:...
to the Royal Society of Edinburgh
Royal Society of Edinburgh
The Royal Society of Edinburgh is Scotland's national academy of science and letters. It is a registered charity, operating on a wholly independent and non-party-political basis and providing public benefit throughout Scotland...
. He took a prominent part, on the liberal
Liberalism
Liberalism is the belief in the importance of liberty and equal rights. Liberals espouse a wide array of views depending on their understanding of these principles, but generally, liberals support ideas such as constitutionalism, liberal democracy, free and fair elections, human rights,...
side, in the ecclesiastical controversy that arose in connexion with Sir John Leslie
John Leslie (physicist)
Sir John Leslie was a Scottish mathematician and physicist best remembered for his research into heat.Leslie gave the first modern account of capillary action in 1802 and froze water using an air-pump in 1810, the first artificial production of ice.In 1804, he experimented with radiant heat using...
's appointment to the post he had vacated, and published a satirical Letter (1806).
Playfair was an opponent of Gottfried Leibniz
Gottfried Leibniz
Gottfried Wilhelm Leibniz was a German philosopher and mathematician. He wrote in different languages, primarily in Latin , French and German ....
's vis viva
Vis viva
In the history of science, vis viva is an obsolete scientific theory that served as an elementary and limited early formulation of the principle of conservation of energy...
principle, an early version of the conservation of energy
Conservation of energy
The nineteenth century law of conservation of energy is a law of physics. It states that the total amount of energy in an isolated system remains constant over time. The total energy is said to be conserved over time...
. In 1808, he launched an attack on John Smeaton
John Smeaton
John Smeaton, FRS, was an English civil engineer responsible for the design of bridges, canals, harbours and lighthouses. He was also a capable mechanical engineer and an eminent physicist...
and William Hyde Wollaston
William Hyde Wollaston
William Hyde Wollaston FRS was an English chemist and physicist who is famous for discovering two chemical elements and for developing a way to process platinum ore.-Biography:...
's work championing the theory.
Although a wealthy man, Playfair was buried in an unmarked grave in Old Calton Cemetery
Old Calton Cemetery
Old Calton Cemetery is a graveyard in Edinburgh, Scotland. It is located on Calton Hill, to the north-east of the city centre. The burial ground was opened in 1718, and is the resting place of several notable Edinburgh persons, including philosopher David Hume, publisher William Blackwood and...
, on Waterloo Place in Edinburgh. However, the monument to his memory, on Calton Hill, is visible from the spot.
Family
John's brothers were architect James PlayfairJames Playfair
James Playfair was a Scottish architect who worked largely in the Neoclassical tradition. He was born in Benvie near Dundee, where his father was the parish minister. He was the brother of William Playfair the engineer, and the mathematician John Playfair...
and engineer William Playfair
William Playfair
William Playfair was a Scottish engineer and political economist, the founder of graphical methods of statistics....
. His nephew, William Henry Playfair
William Henry Playfair
William Henry Playfair FRSE was one of the greatest Scottish architects of the 19th century, designer of many of Edinburgh's neo-classical landmarks in the New Town....
(1790-1857) was an eminent architect in Scotland. His nephew designed the monument to his memory on Calton Hill.
Honours
- Fellow of the Royal Society of Edinburgh
- Fellow of the Royal Society of London, 1807
- CraterImpact craterIn the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
s on MarsMarsMars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
and the MoonMoonThe Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
were named in his honor.
Critical bibliography
A four-volume collected edition of Playfair's works, with a memoir by James G. Playfair, appeared at Edinburgh in 1822.His writings include a number of essays contributed to the Edinburgh Review
Edinburgh Review
The Edinburgh Review, founded in 1802, was one of the most influential British magazines of the 19th century. It ceased publication in 1929. The magazine took its Latin motto judex damnatur ubi nocens absolvitur from Publilius Syrus.In 1984, the Scottish cultural magazine New Edinburgh Review,...
from 1804 onwards, various papers in the Philosophical Transactions of the Royal Society
Philosophical Transactions of the Royal Society
The Philosophical Transactions of the Royal Society is a scientific journal published by the Royal Society of London. It was established in 1665, making it the first journal in the world exclusively devoted to science, and it has remained in continuous publication ever since, making it the world's...
(including his earliest publication, "On the Arithmetic of Impossible Quantities", 1779, and an "Account of the Lithological Survey of Schehallion", 1811) and in the Transactions of the Royal Society of Edinburgh ("On the Causes which Affect the Accuracy of Barometrical Measurements" and others), the articles "Aepinus" and "Physical Astronomy", and a "Dissertation on the Progress of Mathematical and Physical Science since the Revival of Learning in Europe" in the Encyclopædia Britannica
Encyclopædia Britannica
The Encyclopædia Britannica , published by Encyclopædia Britannica, Inc., is a general knowledge English-language encyclopaedia that is available in print, as a DVD, and on the Internet. It is written and continuously updated by about 100 full-time editors and more than 4,000 expert...
(Supplement to fourth, fifth and sixth editions).
His Elements of Geometry first appeared in 1795 and has passed through many editions; his Outlines of Natural Philosophy (2 vols., 1812-1816) consist of the propositions and formulae which were the basis of his class lectures. Playfair's contributions to pure mathematics
Pure mathematics
Broadly speaking, pure mathematics is mathematics which studies entirely abstract concepts. From the eighteenth century onwards, this was a recognized category of mathematical activity, sometimes characterized as speculative mathematics, and at variance with the trend towards meeting the needs of...
were not considerable, his papers "On the Arithmetic of Impossible Quantities" and "On the Causes which Affect the Accuracy of Barometrical Measurements", and his Elements of Geometry, all already referred to, being the most important. His lives of Matthew Stewart, Hutton
James Hutton
James Hutton was a Scottish physician, geologist, naturalist, chemical manufacturer and experimental agriculturalist. He is considered the father of modern geology...
, and Robison
John Robison (physicist)
John Robison FRSE was a Scottish physicist and mathematician. He was a professor of philosophy at the University of Edinburgh....
, many of his review
Review
A review is an evaluation of a publication, a product or a service, such as a movie , video game, musical composition , book ; a piece of hardware like a car, home appliance, or computer; or an event or performance, such as a live music concert, a play, musical theater show or dance show...
s, and above all his "Dissertation" are of the utmost value.