Samuel Molyneux FRS (16 July 1689 – 13 April 1728) was an amateur astronomer and politician who sat in the

British House of Commons The House of Commons is the lower house of the Parliament of the United Kingdom. Like the upper house, the House of Lords, it meets in the Palace of Westminster in London, England. The House of Commons is an elected body consisting of 650 memb ...

between 1715 and 1728 and in the

Irish House of Commons The Irish House of Commons was the lower house of the Parliament of Ireland that existed from 1297 until the end of 1800. The upper house was the Irish House of Lords, House of Lords. The membership of the House of Commons was directly elected, ...

from 1727 to 1728. His work with

James Bradley James Bradley (September 1692 – 13 July 1762) was an English astronomer and priest who served as the third Astronomer Royal from 1742. He is best known for two fundamental discoveries in astronomy, the aberration of light (1725–1728), and ...

attempting to measure stellar parallax led to the discovery of the

aberration of light In astronomy, aberration (also referred to as astronomical aberration, stellar aberration, or velocity aberration) is a phenomenon where celestial objects exhibit an apparent motion about their true positions based on the velocity of the obser ...

. The aberration was the first definite evidence that the earth moved and that

Copernicus Nicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath who formulated a mathematical model, model of Celestial spheres#Renaissance, the universe that placed heliocentrism, the Sun rather than Earth at its cen ...

and

Kepler Johannes Kepler (27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of p ...

were correct.Science and Its Times via In addition to his astronomical works, Molyneux wrote about the natural history and other features of

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. He died in suspicious circumstances.

Early life

Molyneux was born in Chester, England in 1689 and was the second son of William Molyneux, who was known for his work related to optics. His mother was Lucy Domville, daughter of Sir

William Domville William Domville (or Domvile) (1609–1689) was a leading Irish politician, barrister and Constitutional writer of the Restoration era. Due to the great trust which the English Crown had in him, he served as Attorney General for Ireland throug ...

, the

Attorney General for Ireland The Attorney-General for Ireland was an Kingdom of Ireland, Irish and then, from 1801 under the Acts of Union 1800, United Kingdom government office-holder. He was senior in rank to the Solicitor-General for Ireland: both advised the Crown on ...

. Molyneux studied at

Trinity College Dublin Trinity College Dublin (), officially titled The College of the Holy and Undivided Trinity of Queen Elizabeth near Dublin, and legally incorporated as Trinity College, the University of Dublin (TCD), is the sole constituent college of the Unive ...

, where he earned a

Bachelor of Arts A Bachelor of Arts (abbreviated B.A., BA, A.B. or AB; from the Latin ', ', or ') is the holder of a bachelor's degree awarded for an undergraduate program in the liberal arts, or, in some cases, other disciplines. A Bachelor of Arts deg ...

(BA) in 1708 and a

Master of Arts A Master of Arts ( or ''Artium Magister''; abbreviated MA or AM) is the holder of a master's degree awarded by universities in many countries. The degree is usually contrasted with that of Master of Science. Those admitted to the degree have ...

(MA) in 1710. He was elected a Fellow of the Royal Society in 1712.

Astronomical work

Molyneux is best known for his work with Bradley in attempting to measure the parallax of Gamma Draconis leading to the discovery of the

. Molyneux was interested in detecting

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

that others such as

Robert Hooke Robert Hooke (; 18 July 16353 March 1703) was an English polymath who was active as a physicist ("natural philosopher"), astronomer, geologist, meteorologist, and architect. He is credited as one of the first scientists to investigate living ...

had attempted but failed to detect. Unlike Hooke, Molyneux had large amounts of patience and had resources to expend. Like Hooke, Molyneux decided to take advantage of Gamma Draconis being a star that passes directly overhead in London, minimizing the effects of atmospheric refraction on its apparent position when it does so. Molyneux commissioned a larger set of telescopes and employed

as an expert who had more astronomical and mathematical knowledge. Working together, Bradley and Molyneux performed over 80 observations to a precision of greater than 1

arcsecond A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

from December 1725 until late in 1727. Measurements of this precision had never before been performed with telescopes. Bradley and Molyneux were surprised to find that rather than detect a parallax they detected an unexplained wobble of the star. Moreover, similar wobbles were found by Bradley using another high-precision telescope for some 200 other stars. Molyneux died shortly before Bradley realized that the observed changes they were seeing was in fact due to the aberration of light.

Political career

Molyneux was Member of Parliament (MP) for

Bossiney Bossiney (, meaning ''Kyni's dwelling'') is a village in north Cornwall, England, United Kingdom. It is north-east of the larger village of Tintagel which it adjoins: further north-east are the Rocky Valley and Trethevy. Until 1832 the village, ...

in Cornwall from 1715 to 1722, for

St Mawes St Mawes () is a village on the end of the Roseland Peninsula, in the eastern side of Falmouth, Cornwall, Falmouth harbour, on the south coast of Cornwall, England. The village, formerly two separate hamlets, lies on the east bank of the Carri ...

from 1726 to 1727, and for

Exeter Exeter ( ) is a City status in the United Kingdom, cathedral city and the county town of Devon in South West England. It is situated on the River Exe, approximately northeast of Plymouth and southwest of Bristol. In Roman Britain, Exeter w ...

from 1727 to 1728. He served as Secretary to the Prince of Wales from 1715 to 1727 and as Lord of the Admiralty from 1727 to 1728. Between 1727 and 1728 he represented Dublin University in the

Death and legacy

Molyneux married Lady Elizabeth Capel, daughter of Algernon Capell, 2nd Earl of Essex, on 5 April 1717. In 1728, he suffered a fit while in the House of Commons. He was treated by court anatomist Nathaniel St André, but the treatment did not prove successful, and Molyneux died in Kew in April. On the night of the death, St André eloped with Molyneux's wife, Elizabeth, the two marrying in 1730. Samuel Madden, a relative of Molyneux's, claimed that St André had poisoned the MP. Although St André won an action for

defamation Defamation is a communication that injures a third party's reputation and causes a legally redressable injury. The precise legal definition of defamation varies from country to country. It is not necessarily restricted to making assertions ...

, he found himself unable to secure regular work.

Notes

External links

* {{DEFAULTSORT:Molyneux, Samuel 1689 births 1728 deaths Alumni of Trinity College Dublin 18th-century British astronomers British MPs 1715–1722 British MPs 1727–1734 Fellows of the Royal Society Irish MPs 1727–1760 Lords of the Admiralty Members of the Parliament of Great Britain for Exeter Members of the Parliament of Ireland (pre-1801) for Dublin University Members of the Parliament of Great Britain for constituencies in Cornwall People from Chester Members of the Privy Council of Ireland