Editing Nevil Maskelyne

{{Short description|British astronomer and physicist (1732–1811)}}
{{Other people}}
{{Use British English|date=October 2011}}
{{Use dmy dates|date=April 2020}}
{{Infobox scientist
|name              = Nevil Maskelyne
|honorific_suffix  = {{post-nominals|country=GBR|FRS|FRSE|size=100%}}
|image             = Maskelyne Nevil.jpg
|caption            = 
|birth_date        = {{birth-date|6 October 1732}}
|birth_place       = [[London]], England
|death_date        = {{death-date and age|9 February 1811|6 October 1732}}
|death_place       = [[Greenwich, Kent]], England
|field             = [[Astronomy]]
|work_institutions = {{ubl|Fellow of the [[Royal Society]] (1758)|Fellow of the [[Royal Society of Edinburgh]] (1784)|Honorary Member of the French Institute}}
|alma_mater        = 
|doctoral_advisor  = 
|doctoral_students = 
|title             = [[Astronomer Royal]]
|influences        = 
|influenced        = 
|prizes            = [[Copley medal|Royal Society Copley Medal]] (1775)
|footnotes         = 
|signature         = 
}}

'''Nevil Maskelyne''' {{post-nominals|country=GBR|FRS|FRSE}} ({{IPAc-en|ˈ|m|æ|s|k|ə|l|ɪ|n}};<ref>{{cite web |last1=Higgitt |first1=Rebekah |title=Hero or villain? Nevil Maskelyne's posthumous reputation |url=https://www.youtube.com/watch?v=XwINph0g34o |archive-url=https://ghostarchive.org/varchive/youtube/20211211/XwINph0g34o| archive-date=2021-12-11 |url-status=live|website=YouTube |publisher=The Royal Society |access-date=7 February 2020}}{{cbignore}}</ref> 6 October 1732 – 9 February 1811) was the fifth British [[Astronomer Royal]].{{efn|Dates before 14 September 1752 are in the Julian calendar, which was in force in the UK at that time.}} He held the office from 1765 to 1811. He was the first person to scientifically measure the [[mass]] of the planet Earth.<ref>Dr. Maskelyne F.R.S. Astronomer Royal, J. Asperne, London, 1804</ref> He created ''[[The Nautical Almanac]]'', in full the ''British Nautical Almanac and Astronomical [[Ephemeris]] for the Meridian of the Royal Observatory at Greenwich'' using [[Tobias Mayer]]'s corrections for [[Euler]]'s ''Lunar Theory'' tables.

==Biography==
Maskelyne was born in London, the third son of Edmund Maskelyne of [[Purton]] in [[Wiltshire]], and his wife, Elizabeth Booth. Maskelyne's father died when he was 12, leaving the family in reduced circumstances. Maskelyne attended [[Westminster School]] and was still a pupil there when his mother died in 1748. His interest in astronomy had begun while at Westminster School, shortly after the [[eclipse]] of 14 July 1748.<ref name="Howse">{{cite book | author=Howse, Derek | title = Nevil Maskelyne: The Seaman's Astronomer | year = 1989 | publisher=[[Cambridge University Press]] | isbn = 052136261X}}</ref>

Maskelyne entered [[St Catharine's College, Cambridge]] in 1749, graduating as seventh [[Wrangler (University of Cambridge)|wrangler]] in 1754.<ref>{{acad|MSKN749N|name=Nevil Maskelyne}}</ref> [[Ordained]] as a [[Minister (Christianity)|minister]] in 1755, he became a [[fellow]] of [[Trinity College, Cambridge]] in 1756 and a Fellow of the [[Royal Society]] in 1758.<ref>{{cite web|title=Election Certificate|url=https://collections.royalsociety.org/DServe.exe?dsqIni=Dserve.ini&dsqApp=Archive&dsqDb=Catalog&dsqSearch=RefNo==%27EC%2F1758%2F04%27&dsqCmd=Show.tcl|website=Royal Society Library|access-date=16 April 2015|ref=EC/1758/04}}</ref> Maskelyne became a member of the [[American Philosophical Society]], elected in 1771.<ref>{{Cite web|url=https://search.amphilsoc.org/memhist/search?creator=Nevil+&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced|title = APS Member History}}</ref>

Originally pursuing his career as a [[Church of England]] minister, he was Rector of [[Shrawardine]] in [[Shropshire]] from 1775 to 1782 and then Rector of [[North Runcton]] in [[Norfolk]] from 1782. In 1784 he was elected a Fellow of the [[Royal Society of Edinburgh]]. His proposers were [[John Playfair]], [[John Robison (physicist)|John Robison]] and [[Dugald Stewart]].<ref>{{cite book|title=Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002|date=July 2006|publisher=[[The Royal Society of Edinburgh]]|isbn=0-902-198-84-X|url=https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|access-date=30 August 2017|archive-url=https://web.archive.org/web/20160304074135/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|archive-date=4 March 2016|url-status=dead}}</ref>  
On 21 August 1784 Maskelyne married Sophia Rose, then of [[St Andrew Holborn (parish)|St Andrew Holborn, Middlesex.]]<ref>{{Cite web|url=https://www.ancestry.com/interactive/1623/31281_a100986-00037?pid=215083&backurl=https://search.ancestry.com/cgi-bin/sse.dll?dbid%3D1623%26h%3D215083%26indiv%3Dtry%26o_vc%3DRecord:OtherRecord%26rhSource%3D1981&treeid=&personid=&hintid=&usePUB=true&usePUBJs=true|title=London, England, Church of England Marriages and Banns, 1754-1932 for Nevil Maskelyne|date=21 August 1784|website=Ancestry.com|access-date=19 December 2018}}</ref> Their only child, Margaret (25 June 1785<ref>{{Cite web|url=https://search.ancestry.com/cgi-bin/sse.dll?dbid=1624&h=152721897&indiv=try&o_vc=Record:OtherRecord&rhSource=1623|title=London, England, Church of England Baptisms, Marriages and Burials, 1538-1812 for Nevil Maskelyne|date=26 July 1785|website=Ancestry.com|access-date=19 December 2018}}</ref>–1858), was the mother of [[Nevil Story Maskelyne|Mervyn Herbert Nevil Story-Maskelyne]] (1823–1911) professor of mineralogy at Oxford (1856–95).  Maskelyne's younger sister, [[Margaret Clive|Margaret]], married [[Robert Clive]].

Maskelyne is buried in the churchyard of [[St Mary's Church, Purton|St Mary the Virgin]], the parish church of the village of [[Purton]], Wiltshire, England.<ref>Maskelyne's grave can be seen by going through the church gates and veering to the right, against the right outside wall of the church.</ref>

==Career==

===Measurement of longitude===
In 1760 the [[Royal Society]] appointed Maskelyne as an astronomer on one of their expeditions to observe the 1761 [[transit of Venus]]. He and [[Robert Waddington (mathematician)|Robert Waddington]] were sent to the island of [[Saint Helena]] in the [[South Atlantic]]. This was an important observation since accurate measurements would allow the accurate calculation of Earth's distance from the Sun, which would in turn allow the actual rather than the relative scale of the [[Solar System]] to be calculated. This would allow, it was argued, the production of more accurate astronomical tables, in particular those predicting the motion of the Moon.<ref>{{cite book|last1=Woolf|first1=Harry|title=The Transits of Venus. A study of eighteenth-century science|date=1959|publisher=[[Princeton University Press]]|location=Princeton, NJ}}</ref>

Bad weather prevented observation of the transit, but Maskelyne used his journey to trial a method of determining [[longitude]] using the position of the moon, which became known as the [[Lunar distance (navigation)|lunar distance method]].<ref>Nevil Maskelyne [http://cudl.lib.cam.ac.uk/view/MS-RGO-00004-00150/1 Journal of a Voyage to St Helena], RGO 4/150, Cambridge Digital Library</ref> He returned to England, resuming his position as [[curate]] at [[Chipping Barnet]] in 1761, and began work on a book, publishing the lunar-distance method of longitude calculation and providing tables to facilitate its use in 1763 in ''The British Mariner's Guide'', which included the suggestion that to facilitate the finding of [[longitude]] at sea, lunar distances should be calculated beforehand for each year and published in a form accessible to navigators.<ref name=EB1911/>

In 1763 the [[Board of Longitude]] sent Maskelyne to [[Barbados]] in order to carry out an official trial of three contenders for a [[Longitude prize|Longitude reward]]. He was to carry out observations on board ship and to calculate the longitude of the capital, [[Bridgetown]] by observation of [[Jupiter]]'s satellites. The three methods on trial were [[John Harrison]]'s sea watch (now known as [[John Harrison#H4|H4]]), [[Tobias Mayer]]'s lunar tables and a marine chair made by Christopher Irwin, intended to help observations of Jupiter's satellites on board ship. Both Harrison's watch and [[Lunar distance (navigation)|lunar-distance]] observations based on Mayer's lunar tables produced results within the terms of the [[Longitude Act]], although the former appeared to be more accurate. Harrison's watch had produced Bridgetown's longitude with an error of less than ten miles, while the lunar-distance observations were accurate to within 30 nautical miles.

Maskelyne reported the results of the trial to the Board of Longitude on 9 February 1765.<ref>{{cite web|title=Confirmed Minutes of the Board of Longitude|url=http://cudl.lib.cam.ac.uk/view/MS-RGO-00014-00005/79|website=Cambridge Digital Library}}</ref> On 26 February 1765 he had been appointed Astronomer Royal<ref name="Howse" /> following the unexpected death of [[Nathaniel Bliss]] in 1764; making him ''ex officio'' a Commissioner of Longitude. The Commissioners understood that the timekeeping and astronomical methods of finding longitude were complementary. The lunar-distance method could more quickly be rolled out, with Maskelyne's proposal that tables like those in his "The British Mariner's Guide" be published for each year. This proposal led to the establishment of [[The Nautical Almanac]], the production of which, as Astronomer Royal, Maskelyne oversaw. Taking even occasional astronomical observations was also the only way to check that a timekeeper was keeping good time over the course of a long voyage. The Commissioners also needed to know that more than one sea watch could be made, and that Harrison's methods could be communicated to other watchmakers.<ref>{{cite book|last1=Dunn|first1=Richard|last2=Higgitt|first2=Rebekah|title=Finding Longitude: How Ships, Clocks and Stars Helped Solve the Longitude Problem|date=2014|publisher=Collins|location=Glasgow|isbn=978-0007525867}}</ref>

The Board of Longitude therefore decided that rewards should be given to Harrison (£10,000), Mayer (£3000, posthumously) and others involved in helping to develop the lunar-distance method.<ref>{{cite web|last1=Higgitt|first1=Rebekah|title=Barbados or bust: longitude on trial|website=[[TheGuardian.com]]|date=9 September 2013|url=https://www.theguardian.com/science/the-h-word/2013/sep/09/history-science-longitude-maskelyne-barbados|access-date=15 April 2015}}</ref><ref>{{cite journal|last1=Howse|first1=Derek|title=Britain's Board of Longitude: The Finances, 1714-1828|journal=The Mariner's Mirror|date=1998|volume=84|issue=4|pages=400–417|url=http://blogs.rmg.co.uk/wp-content/uploads/sites/5/2013/03/howse.pdf|access-date=16 April 2015|doi=10.1080/00253359.1998.10656713|archive-date=23 May 2014|archive-url=https://web.archive.org/web/20140523173104/http://blogs.rmg.co.uk/wp-content/uploads/sites/5/2013/03/howse.pdf|url-status=dead}}</ref> Harrison was told that a further reward of £10,000 would be forthcoming if he could demonstrate the replicability of his watch. Although Harrison and his son later accused Maskelyne of bias against the timekeeping method, charges repeated by authors such as [[Dava Sobel]] and [[Rupert Gould]], Maskelyne never submitted a method or an idea of his own for consideration by the Board of Longitude. He was to play a significant role in having [[Marine chronometer|marine timekeepers]], as well as the lunar-distance method, developed, tested and used on board voyages of exploration.<ref name="Howse" />

Since the observations that fed into the ''[[Nautical Almanac]]'' were made at the [[Royal Greenwich Observatory|Royal Observatory, Greenwich]], the [[Greenwich meridian]] became the reference for measurements of longitude in the Royal Navy, and on British Admiralty charts. It was subsequently chosen for adoption as the international [[Prime Meridian]] in 1884.<ref>(JR Wills The Royal Society)</ref><ref>{{cite book|last1=Dunn|first1=Richard|last2=Higgitt|first2=Rebekah|title=Finding Longitude: How Ships, Clocks and Stars Helped Solve the Longitude Problem|date=2014|publisher=Collins|location=Glasgow|isbn=978-0007525867|page=221}}</ref>

===Measurement of latitude===
Maskelyne took a great interest in various [[geodetics|geodetical]] operations, including the measurement of the length of a degree of latitude in [[Maryland]] and [[Pennsylvania]],<ref name="PTRS323">Philosophical Transactions of the Royal Society. lviii. 323</ref><ref name=EB1911/> executed by [[Charles Mason|Mason]] and [[Jeremiah Dixon|Dixon]] in 1766 – 1768, and later the determination of the relative longitude of [[Greenwich]] and Paris.<ref name="PTRS151">Philosophical Transactions of the Royal Society. lxxvii. 151</ref><ref name=EB1911/> On the French side the work was conducted by [[Dominique, comte de Cassini|Count Cassini]], [[Adrien-Marie Legendre|Legendre]], and [[Pierre Méchain|Méchain]]; on the English side by [[William Roy|General Roy]]. This triangulation was the beginning of the [[Principal Triangulation of Great Britain|great trigonometrical survey]] which was subsequently extended all over Britain. His observations appeared in four large folio volumes from 1776 to 1811,<ref name=EB1911/> some of them being reprinted in [[Samuel Vince]]'s ''Elements of Astronomy''.<ref>{{cite book | last = Vince | first = Samuel | author-link = Samuel Vince | title = The Elements of Astronomy: Designed for the Use of Students in the University | publisher=J. Smith | year = 1811 | url =https://archive.org/details/elementsofastron00vincrich}}</ref>

===Schiehallion experiment===
In 1772 Maskelyne proposed to the [[Royal Society]] what was to become known as the [[Schiehallion experiment]] (named after the Scottish mountain on which it was performed), for the determination of the [[Earth]]'s density using a [[plumb line]]. He was not the first to suggest this, [[Pierre Bouguer]] and [[Charles-Marie de la Condamine]] having attempted the same experiment in 1738 in the [[Andes]].

Maskelyne performed his experiment in 1774 on [[Schiehallion]] in [[Perthshire]], Scotland,<ref name="PTRS495">Philosophical Transactions of the Royal Society. 1. 495</ref> the mountain being chosen due to its regular conical shape which permitted a reasonably accurate determination of its volume. The apparent difference of [[latitude]] between two stations on opposite sides of the mountain were compared with the real difference of latitude obtained by [[triangulation]].<ref name=EB1911/>

From Maskelyne's observations [[Charles Hutton]] deduced a density for the earth 4.5 times that of water (the modern value is 5.515).<ref name=EB1911/>

==Other work==
Maskelyne's first contribution to astronomical literature was ''A Proposal for Discovering the Annual [[Parallax]] of [[Sirius]]'', published in 1760.<ref name="PTRS889">Philosophical Transactions of the Royal Society. ii. 889</ref><ref name=EB1911/> Subsequent contributions to the ''Transactions'' contained his observations of the transits of [[Venus]] (1761 and 1769), on the tides at [[Saint Helena]] (1762), and on various astronomical phenomena at Saint Helena (1764) and at [[Barbados]] (1764).<ref name=EB1911/>

Maskelyne also introduced several practical improvements, such as the measurement of time to tenths of a second and prevailed upon the government to replace [[John Bird (astronomer)|Bird]]'s [[Mural instrument|mural quadrant]] by a [[repeating circle]] 6 feet (1.8 m) in diameter. The new instrument was constructed by [[Edward Troughton]] but Maskelyne did not live to see it completed.<ref name=EB1911>{{EB1911|wstitle=Maskelyne, Nevil|volume=17|last1= Clerke |first1= Agnes Mary |author1-link= Agnes Mary Clerke |page=837|inline=1}}</ref>

==Maskelyne in literature and the arts==
[[File:Grave of Nevil Maskelyne.JPG|right|thumb|Maskelyne's tomb in [[Purton]], Wiltshire]]
* Maskelyne features prominently in [[Dava Sobel]]'s 1995 book, ''[[Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time]]'', as well as the [[Longitude (TV serial)|television serial]] based on the book, where he is portrayed by [[Samuel West]].<ref>{{cite web |title=Longitude © (1999) |url=http://movie-dude.com/[Film]%20Longitude%20(1999).htm |access-date=22 June 2021}}</ref>
* Maskelyne is a supporting character in the novel ''[[Mason & Dixon]]'' by [[Thomas Pynchon]]. He and [[Charles Mason]] (and briefly, [[Jeremiah Dixon]] before he returns to [[Cape Town]]) meet on Saint Helena - with the characters of the two clashing while they spend time which each other.
* Maskelyne is portrayed as "Dr. Vickery" in [[Kate Grenville]]'s semi-historical novel ''[[The Lieutenant (novel)|The Lieutenant]]''.

==Honours==

* 1775 – Awarded the Royal Society's [[Copley Medal]]<ref>{{Cite web |title=Copley Medal {{!}} Royal Museums Greenwich |url=https://www.rmg.co.uk/collections/objects/rmgc-object-249548 |access-date=2024-08-25 |website=www.rmg.co.uk}}</ref>
* 1776 – Elected a Member of the [[Russian Academy of Sciences|Saint Petersburg Academy of Sciences]].<ref>{{cite web|title=Papers of Nevil Maskelyne: Certificate and seal from Catherine the Great, Russia|url=http://cudl.lib.cam.ac.uk/view/MS-REG-00009-00037/1|publisher=Cambridge Digital Library|access-date=19 January 2015}}</ref>
* 1778 – Elected a Foreign Honorary Member of the [[American Academy of Arts and Sciences]].<ref name=AAAS>{{cite web|title=Book of Members, 1780–2010: Chapter M|url=http://www.amacad.org/publications/BookofMembers/ChapterM.pdf |archive-url=https://web.archive.org/web/20060618085944/http://amacad.org/publications/BookofMembers/ChapterM.pdf |archive-date=2006-06-18 |url-status=live|publisher=[[American Academy of Arts and Sciences]]|access-date=28 July 2014}}</ref>
* The lunar crater [[Maskelyne (crater)|Maskelyne]] in the [[Sea of Tranquility]] is named after him.
* [[William Wales (astronomer)|William Wales]] named the [[Maskelyne Islands]] in southern Malekule, [[Vanuatu]] after him while on [[James Cook]]'s second voyage on [[HMS Resolution (1771)|HMS ''Resolution'']].<ref>{{cite book|last1=Wales|first1=William|title=The Original Astronomical Observations, Made in the Course of a Voyage towards the South Pole, and Around the World|date=1777|location=London|page=lv}}</ref>
*Also during Cook's second voyage, the colony at [[Botany Bay]] had a small area next to the newly established observatory named '''Point Maskelyne'''.<ref>Map of Port Jackson (now known as Sydney) 1788</ref>

==Works==
[[File:Maskelyne, Nevil – Tables requisite to be used with the astronomical and nautical ephemeris for finding the latitude and longitude at sea, 1781 – BEIC 782957.jpg|thumb|''Tables requisite to be used with the astronomical and nautical ephemeris for finding the latitude and longitude at sea'', 1781]]
* {{Cite book|title=Tables requisite to be used with the astronomical and nautical ephemeris for finding the latitude and longitude at sea|volume=|publisher=William Richardson|location=London|year=1781|language=en|url=https://gutenberg.beic.it/webclient/DeliveryManager?pid=782957}}

==Notes==
{{notelist}}

==References==
{{reflist}}

== Further reading ==
* {{cite journal |last=Delambre |first=Jean-Baptiste-Joseph |author-link=Jean Baptiste Joseph Delambre |title=Biographical Account of the Rev. Nevil Maskelyne, D. D. Astronomer Royal |journal=[[Annals of Philosophy]] |year=1813 |volume=1 |number=6 |pages=401–414 |url=https://books.google.com/books?id=2xsAAAAAMAAJ&pg=PA401 }}

==External links==
{{commons category|Nevil Maskelyne (astronomer)}}
* [http://janus.lib.cam.ac.uk/db/node.xsp?id=EAD%2FGBR%2F0180%2FRGO%204 Online catalogue of Maskelyne's working papers (part of the Royal Greenwich Observatory Archives held at Cambridge University Library)]
* [http://cudl.lib.cam.ac.uk/view/ES-LON-00027/1 Essay on Nevil Maskelyne, Cambridge Digital Library]
 
{{Authority control}}

{{Astronomers Royal}}
{{Copley Medallists 1751-1800}}

{{DEFAULTSORT:Maskelyne, Nevil}}
[[Category:1732 births]]
[[Category:1811 deaths]]
[[Category:Anglican clergy from London]]
[[Category:Academics from London]]
[[Category:Alumni of St Catharine's College, Cambridge]]
[[Category:Fellows of Trinity College, Cambridge]]
[[Category:Astronomers Royal]]
[[Category:18th-century British astronomers]]
[[Category:18th-century English Anglican priests]]
[[Category:Fellows of the American Academy of Arts and Sciences]]
[[Category:Fellows of the Royal Society]]
[[Category:Fellows of the Royal Society of Edinburgh]]
[[Category:Members of the French Academy of Sciences]]
[[Category:People educated at Westminster School, London]]
[[Category:Recipients of the Copley Medal]]
[[Category:19th-century British astronomers]]
[[Category:Members of the American Philosophical Society]]
[[Category:Maskelyne family|Nevil]]