View source for Biography:William Thomson, 1st Baron Kelvin

{{short description|British physicist, engineer and mathematician (1824–1907)}}
{{other people|William Thomson}}
{{Infobox officeholder
| name                = The Lord Kelvin
| office              = President of the Royal Society
| honorific-prefix    = The Right Honourable
| honorific-suffix    = {{postnominals|country=GBR|size=100%|OM|GCVO|PC|PRS|FRSE}}
| image               = Baron Kelvin 1906.jpg
| caption             = Kelvin in 1906
| predecessor         = [[Biography:Sir George Stokes, 1st Baronet|Sir George Stokes]]
| successor           = The Lord Lister
| footnotes           = It is believed the "PNP" in his signature stands for "Professor of Natural Philosophy". Note that Kelvin also wrote under the pseudonym "P. Q. R."
| signature           = Lord Kelvin Signature.svg
| birth_date          = {{birth date|1824|06|26|df=y}}
| birth_place         = [[Place:Belfast|Belfast]], [[History:United Kingdom of Great Britain and Ireland|United Kingdom of Great Britain and Ireland]]
| death_date          = {{death date and age|1907|12|17|1824|06|26|df=y}}
| death_place         = Largs, Scotland, [[History:United Kingdom of Great Britain and Ireland|United Kingdom of Great Britain and Ireland]]
| spouse              = {{marriage|Margaret Crum<br />|1852|1870|end=died}}<br />{{marriage|Frances Blandy<br />|1874|1907}}<ref>{{cite web |url=http://www.electricscotland.com/history/other/william_thomson.htm |title=Significant Scots. William Thomson (Lord Kelvin) |author=<!--Not stated--> |website=Electric Scotland |access-date=23 July 2018 }}</ref>
| children            = None<ref>{{cite web |url=https://www.westminster-abbey.org/abbey-commemorations/commemorations/william-thomson-lord-kelvin/ |title=William Thomson, Lord Kelvin. Scientist, Mathematician and Engineer |author=<!--Not stated--> |website=Westminster Abbey |access-date=23 July 2018 |quote=His first wife was Margaret Crum and he married secondly Frances Blandy but had no children.}}</ref>
| nationality         = British<ref>{{cite journal|last=Grabiner |first=Judy |date=2002 |title=''Creators of Mathematics: The Irish Connection'' (book review) |url=http://www.maths.tcd.ie/pub/ims/bull48/BR4801.pdf |journal=Irish Math. Soc. Bull. |volume=48 |page=67 |doi=10.33232/BIMS.0048.65.68 |access-date=27 June 2016}}</ref><ref name="britannica.com" />
| party               = Liberal (1865–1886)<br />Liberal Unionist (from 1886)
| term_start          = 1 December 1890
| term_end            = 30 November 1895
| module              = {{Infobox scientist | embed = yes
| workplaces  = [[Organization:University of Glasgow|University of Glasgow]]
| alma_mater  = {{unbulleted list
 |Royal Belfast Academical Institution
 |Glasgow University
 |Peterhouse, Cambridge
}}
| doctoral_advisor  = <!--Not applicable, but leave as template placeholder-->
| academic_advisors = William Hopkins
| doctoral_students = <!--Not applicable, but leave as template placeholder-->
| notable_students  = {{unbulleted list|[[Biography:John William Strutt, 3rd Baron Rayleigh|Lord Rayleigh]]<ref name=kelvinrayleigh>{{cite conference|author-last=Ranford|author-first=Paul|title=John William Strutt-- the 3rd Baron Rayleigh (1842–1919): Recently studied correspondence|date=September 2019|page=25|url=https://www.researchgate.net/publication/338819094}}</ref>|William Edward Ayrton}}
| known_for = {{hidden|List|{{Plainlist|
* [[Physics:Joule–Thomson effect|Joule–Thomson effect]]
* [[Physics:Joule–Thomson effect|Joule-Thomson ideal gas coefficient]]
* [[Physics:Voigt–Thomson law|Voigt–Thomson law]]
* Thomson effect (thermoelectric)
* [[Physics:Thermoelectric effect#Thomson relations|Thomson relations]]
* [[Physics:Ampere balance|Kelvin balance]]
* [[Engineering:Binnacle|Kelvin's balls]]
* [[Rayleigh's equation (fluid dynamics)#Background|Kelvin cat's eye pattern]]
* [[Engineering:Kinematic coupling#Kelvin Coupling|Kelvin coupling]]
* [[Physics:Mirror galvanometer|Kelvin's mirror galvanometer]]
* Kelvin material
* [[Physics:Kelvin water dropper|Kelvin water dropper]]
* [[Physics:Kelvin wave|Kelvin wave]]
* [[Physics:Kelvin–Helmholtz instability|Kelvin–Helmholtz instability]]
* [[Astronomy:Kelvin–Helmholtz mechanism|Kelvin–Helmholtz mechanism]]
* Kelvin-Helmholtz luminosity
* Kelvin-Planck statement
* [[Astronomy:Heat death paradox|Kelvin’s heat death paradox]]
* [[Astronomy:Thermal time scale|Kelvin–Helmholtz time scale]]
* [[Physics:Kelvin's minimum energy theorem|Kelvin's minimum energy theorem]]
* [[Weaire–Phelan structure|Kelvin conjecture]]
* [[Weaire–Phelan structure|Kelvin structure]]
* Kelvin foam
* [[Kelvin functions]]
* [[Kelvin transform]]
* [[Kelvin's circulation theorem]]
* [[Physics:Stokes' theorem|Kelvin–Stokes theorem]]
* [[Physics:Kelvin bridge|Kelvin bridge]]
* Kelvin sensing
* [[Physics:Kelvin equation|Kelvin equation]]
* Kelvin-Varley divider
* [[Physics:Kelvin wake pattern|Kelvin wake pattern]]
* Kelvin angle
* Zero Kelvin
* [[Physics:Kelvin probe force microscope|Kelvin probe force microscope]]
* [[Physics:Atomic force microscopy|Kelvin scanning probe]]
* Automatic curb sender
* [[Biology:Cable theory|Cable theory]]
* Dark night sky paradox
* [[Earth:Age of Earth|Earth’s age paradox]]
* [[Depth sounding]]
* [[Dissipation]]
* Gyrostat
* [[Law of squares]]
* [[Physics:First law of thermodynamics|First law of thermodynamics]]
* [[Physics:Second law of thermodynamics|Second law of thermodynamics]]
* [[Physics:Entropy|Entropy]]
* [[Astronomy:Heat death of the universe|Heat death of the universe]]
* [[Physics:Magnetic vector potential|Magnetic vector potential]]
* [[Physics:Magnetoresistance|Magnetoresistance]]
* Maxwell’s demon
* [[Physics:Piezoresistive effect|Piezoresistive effect]]
* Siphon recorder
* [[Stationary phase approximation]]
* [[Astronomy:Dark matter|Dark matter]]
* [[Tide-predicting machine]]
* [[Vortex theory of the atom]]
* [[Chirality|Coining the term ''chirality'']]
* [[Physics:Thermodynamics|Coining the term ''thermodynamics'']]<ref name=kelvin1849>{{cite journal | last=Thomson | first=William | title=An Account of Carnot's Theory of the Motive Power of Heat; with Numerical Results deduced from Regnault's Experiments on Steam | journal=Transactions of the Royal Society of Edinburgh| volume=16 | issue=5 | year=1849 | doi=10.1017/s0080456800022481 | pages=541–574| s2cid=120335729 | url=https://zenodo.org/record/2133961 }}</ref>
* [[Physics:Kinetic energy|Coining the term ''kinetic energy'']]
}}}}
| author_abbrev_bot =
| author_abbrev_zoo =
| influences        = {{unbulleted list
 |[[Biography:Nicolas Léonard Sadi Carnot|Sadi Carnot]]
 |[[Biography:Rudolf Clausius|Rudolf Clausius]]
 |[[Biography:Julius von Mayer|Julius von Mayer]]
 |[[Biography:James Prescott Joule|James Joule]]
 |[[Biography:Humphry Davy|Humphry Davy]]
}}
| influenced = [[Biography:Andrew Gray (physicist)|Andrew Gray]]
| awards     = {{unbulleted list
 | First Smith's Prize (1845)
 |Royal Medal (1856)
 |Keith Medal (1864)
 |[[Physics:Matteucci Medal|Matteucci Medal]] (1876)
 |Albert Medal (1879)
 |[[Physics:Copley Medal|Copley Medal]] (1883)
 |John Fritz Medal (1905)
}}
}}
}}

'''William Thomson, 1st Baron Kelvin''', {{postnominals|country=GBR|sep=,|OM|GCVO|PC|PRS|FRSE}} (26 June 1824{{snd}}17 December 1907)<ref name=":0" /> was a British [[Biography:Mathematician|mathematician]], [[Physics:Mathematical physics|mathematical physicist]] and [[Engineering:Engineer|engineer]] born in [[Place:Belfast|Belfast]].<ref>* {{Citation|title=Kelvin, Sir William Thomson, Lord|work=The New Oxford Dictionary for Scientific Writers and Editors|year=2009|editor-last=Martin|editor-first=Elizabeth|edition=2nd|publisher=Oxford University Press|doi=10.1093/acref/9780199545155.001.0001|isbn=978-0-19-954515-5|quote=British theoretical and experimental physicist}}
* {{Citation|title=Lord Kelvin Oxford Dictionary of Quotations|year=2014|editor-last=Knowles|editor-first=Elizabeth|edition=8th|publisher=Oxford University Press|doi=10.1093/acref/9780199668700.001.0001|isbn=978-0-19-966870-0 |quote=Lord Kelvin 1824–1907 British physicist and natural philosopher}}
* {{Citation|title=Kelvin, Lord|work=The Concise Oxford Dictionary of Mathematics|year=2014|editor-last=Clapham|editor-first=Christopher|edition=5th|publisher=Oxford University Press|doi=10.1093/acref/9780199679591.001.0001|isbn=978-0-19-967959-1|quote=Kelvin, Lord (1824–1907) The British mathematician, physicist and engineer|editor2-last=Nicholson|editor2-first=James}}
* {{Citation|title=Kelvin, Lord|work=A Dictionary of Chemical Engineering|year=2014|editor-last=Schaschke|editor-first=Carl|publisher=Oxford University Press|doi=10.1093/acref/9780199651450.001.0001|isbn=978-0-19-965145-0|quote=A Belfast-born Scottish scientist}}
* {{Citation|title=Kelvin, Lord|work=A Dictionary of Astronomy|year=2018|editor-last=Ridpath|editor-first=Ian|edition=3rd|publisher=Oxford University Press|doi=10.1093/acref/9780191851193.001.0001|isbn=978-0-19-185119-3|quote=Kelvin, Lord (William Thomson) (1824–1907) Scottish physicist}}
* {{Cite book|title=Lord Kelvin Oxford Essential Quotations|website=Oxford Reference|publisher=Oxford University Press|year=2018|editor-last=Ratcliffe|editor-first=Susan|edition=6th|doi=10.1093/acref/9780191866692.001.0001|quote=Lord Kelvin 1824–1907 British scientist}}
* {{Citation|title=Kelvin, Lord|work=A Dictionary of Physics|year=2019|editor-last=Rennie|editor-first=Richard|edition=8th|publisher=Oxford University Press|doi=10.1093/acref/9780198821472.001.0001|isbn=978-0-19-882147-2|quote=Kelvin, Lord (William Thomson; 1824–1907) British physicist|editor2-last=Law|editor2-first=Jonathan}}
* {{Citation|title=Kelvin, Lord|work=A Dictionary of Chemistry|year=2020|editor-last=Law|editor-first=Jonathan|edition=8th|publisher=Oxford University Press|doi=10.1093/acref/9780198841227.001.0001|isbn=978-0-19-884122-7|quote=Kelvin, Lord (William Thomson; 1824–1907) British physicist, born in Belfast|editor2-last=Rennie|editor2-first=Richard}}</ref> [[Philosophy:Professor of Natural Philosophy (Glasgow)|Professor of Natural Philosophy]] at the [[Organization:University of Glasgow|University of Glasgow]] for 53 years, he did important work in the [[Mathematical analysis|mathematical analysis]] of electricity and formulation of the first and second [[Physics:Laws of thermodynamics|laws of thermodynamics]], and did much to unify the emerging discipline of [[Physics:Physics|physics]] in its contemporary form. He received the Royal Society's [[Physics:Copley Medal|Copley Medal]] in 1883, was its president 1890–1895, and in 1892 was the first British scientist to be elevated to the House of Lords.<ref name="britannica.com">{{cite web|url=http://www.britannica.com/biography/William-Thomson-Baron-Kelvin |publisher=Encyclopædia Britannica |author=Sharlin, Harold I. |date=2019 |access-date=24 January 2020 |title=William Thomson, Baron Kelvin}}</ref>

Absolute temperatures are stated in units of [[Kelvin|kelvin]] in his honour. While the existence of a coldest possible temperature ([[Physics:Absolute zero|absolute zero]]) was known prior to his work, Kelvin is known for determining its correct value as approximately −273.15 degrees [[Celsius]] or −459.67 degrees [[Fahrenheit]]. The [[Physics:Joule–Thomson effect|Joule–Thomson effect]] is also named in his honour.

He worked closely with mathematics professor Hugh Blackburn in his work. He also had a career as an electric telegraph engineer and inventor, which propelled him into the public eye and ensured his wealth, fame and honour. For his work on the [[History:Transatlantic telegraph cable|transatlantic telegraph project]] he was knighted in 1866 by Queen Victoria, becoming Sir William Thomson. He had extensive maritime interests and was most noted for his work on the mariner's compass, which previously had limited reliability.

He was ennobled in 1892 in recognition of his achievements in thermodynamics, and of his opposition to Irish Home Rule,<ref>{{cite journal | last1=Flood | first1=Raymond | last2=McCartney | first2=Mark | last3=Whitaker | first3=Andrew | title=Kelvin and Ireland | journal=Journal of Physics: Conference Series| volume=158 | date=2009-04-28 | doi=10.1088/1742-6596/158/1/011001 | page=011001| s2cid=250690809 }}</ref><ref>{{cite book| author=Randall, Lisa | title=Warped Passages |location=New York | publisher=HarperCollins |year=2005|page=162|isbn=0-06-053109-6}}</ref><ref>{{cite journal | last=Hutchison | first=Iain | title=Lord Kelvin and Liberal Unionism | journal=Journal of Physics: Conference Series | publisher=IOP Publishing | volume=158 | date=2009 | issue=1 | doi=10.1088/1742-6596/158/1/012004 | page=012004| bibcode=2009JPhCS.158a2004H | s2cid=250693895 }}</ref> becoming Baron Kelvin, of Largs in the County of Ayr. The title refers to the River Kelvin, which flows near his laboratory at the University of Glasgow's [[Organization:University of Glasgow#Gilmorehill|Gilmorehill]] home at Hillhead. Despite offers of elevated posts from several world-renowned universities, Kelvin refused to leave Glasgow, remaining until his eventual retirement from that post in 1899.<ref name=":0" /> Active in industrial research and development, he was recruited around 1899 by George Eastman to serve as vice-chairman of the board of the British company Kodak Limited, affiliated with Eastman Kodak.<ref>{{cite journal | last1 = Trainer | first1 = Matthew | year = 2008 | title = Lord Kelvin, Recipient of The John Fritz Medal in 1905 | journal = Physics in Perspective | volume = 10 | pages = 212–223 | doi = 10.1007/s00016-007-0344-4 | s2cid = 124435108 }}</ref> In 1904 he became Chancellor of the University of Glasgow.<ref name=":0" />

His home was the red sandstone mansion Netherhall, in Largs, which he built in the 1870s and where he died. The Hunterian Museum at the University of Glasgow has a permanent exhibition on the work of Kelvin including many of his original papers, instruments, and other artefacts, such as his smoking pipe.

== Early life and work ==
=== Family ===
[[File:Thomson family lineage.png|330px|right|thumb|Thomson family tree: James Thomson (mathematician), James Thomson (engineer), and William Thomson, were all professors at the University of Glasgow; the later two, through their association with William Rankine, another Glasgow professor, worked to form one of the founding schools of thermodynamics.]]
William Thomson's father, James Thomson, was a teacher of mathematics and engineering at the Royal Belfast Academical Institution and the son of a farmer. James Thomson married Margaret Gardner in 1817 and, of their children, four boys and two girls survived infancy. Margaret Thomson died in 1830 when William was six years old.<ref>{{cite web |url=http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Thomson_James.html |title=Biography of William Thomson's father |publisher=Groups.dcs.st-and.ac.uk |access-date=29 October 2011 |archive-date=2 May 2019 |archive-url=https://web.archive.org/web/20190502040147/http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Thomson_James.html |url-status=dead }}</ref>

William and his elder brother James were tutored at home by their father while the younger boys were tutored by their elder sisters. James was intended to benefit from the major share of his father's encouragement, affection and financial support and was prepared for a career in engineering.

In 1832, his father was appointed professor of mathematics at Glasgow and the family moved there in October 1833. The Thomson children were introduced to a broader cosmopolitan experience than their father's rural upbringing, spending mid-1839 in London and the boys were tutored in French in Paris. Much of Thomson's life during the mid-1840s was spent in Germany and the Netherlands. Language study was given a high priority.

His sister, Anna Thomson, was the mother of James Thomson Bottomley FRSE (1845–1926).<ref>{{Cite web |url=http://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp1.pdf |title=Former Fellows of The Royal Society of Edinburgh, 1783–2002 |access-date=30 April 2015 |archive-date=19 September 2015 |archive-url=https://web.archive.org/web/20150919152306/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp1.pdf |url-status=dead }}</ref>

=== Youth ===
 <!--first 3 paragraphs are not cited-->
[[File:PSM V72 D191 William thomson lord kelvin at the age of twenty two.png|thumb|left|upright|William Thomson, aged 22]]
[[File:University, Glasgow, Scotland, ca. 1895.jpg|thumb|The [[Earth:Meander|meander]] of the River Kelvin containing the Neo-Gothic Gilmorehill campus of the University of Glasgow designed by George Gilbert Scott, to which the university moved in the 1870s (photograph 1890s)]]

Thomson had heart problems and nearly died when he was 9 years old. He attended the Royal Belfast Academical Institution, where his father was a professor in the university department. In 1834, aged 10, he began studying at the University of Glasgow, not out of any precociousness; the University provided many of the facilities of an elementary school for able pupils, and this was a typical starting age.

In school, Thomson showed a keen interest in the classics along with his natural interest in the sciences. At the age of 12 he won a prize for translating Lucian of Samosata's ''Dialogues of the Gods'' from Ancient Greek to English.

In the academic year 1839/1840, Thomson won the class prize in [[Astronomy:Astronomy|astronomy]] for his ''Essay on the figure of the Earth'' which showed an early facility for mathematical analysis and creativity. His physics tutor at this time was his namesake, David Thomson.<ref>{{cite web | url=https://homepages.abdn.ac.uk/npmuseum/article/Profs/ThomsonUni.shtml |title = David Thomson 17 Nov 1817 – 31st Jan 1880 | publisher=Aberdeen University}}</ref>

Throughout his life, he would work on the problems raised in the essay as a [[Social:Coping (psychology)|coping]] strategy during times of personal stress. On the title page of this essay Thomson wrote the following lines from Alexander Pope's ''Essay on Man''. These lines inspired Thomson to understand the natural world using the power and method of science:

{{blockquote|
Go, wondrous creature! mount where Science guides; <br />
Go measure earth, weigh air, and state the tides; <br />
Instruct the planets in what orbs to run, <br />
Correct old Time, and regulate the sun;  }}

Thomson became intrigued with [[Biography:Joseph Fourier|Fourier's]] ''Théorie analytique de la chaleur'' and committed himself to study the "Continental" mathematics resisted by a British establishment still working in the shadow of Sir [[Biography:Isaac Newton|Isaac Newton]]. Unsurprisingly, Fourier's work had been attacked by domestic mathematicians, Philip Kelland authoring a critical book. The book motivated Thomson to write his first published scientific paper<ref>{{cite journal | author=P.Q.R. | year = 1841 | title = On Fourier's expansions of functions in trigonometric series | journal = Cambridge Mathematical Journal | volume = 2 | pages = 258–262 }}</ref> under the pseudonym ''P.Q.R.'', defending Fourier, and submitted to the ''Cambridge Mathematical Journal'' by his father. A second P.Q.R. paper followed almost immediately.<ref>{{cite journal | author=P.Q.R. | year = 1841 | title = Note on a passage in Fourier's 'Heat' | journal = Cambridge Mathematical Journal | volume = 3 | pages = 25–27 | url =https://en.wikisource.org/wiki/Note_on_a_Passage_in_Fourier%27s_Heat }}</ref>

While on holiday with his family in Lamlash in 1841, he wrote a third, more substantial P.Q.R. paper ''On the uniform motion of heat in homogeneous solid bodies, and its connection with the mathematical theory of electricity''.<ref>{{cite journal | author=P.Q.R. | year = 1842 | title = On the uniform motion of heat and its connection with the mathematical theory of electricity | doi =10.1017/CBO9780511996009.004 | journal = Cambridge Mathematical Journal | volume = 3 | pages = 71–84 }}</ref> In the paper he made remarkable connections between the mathematical theories of [[Physics:Heat conduction|heat conduction]] and [[Physics:Electrostatics|electrostatics]], an [[Analogy|analogy]] that [[Biography:James Clerk Maxwell|James Clerk Maxwell]] was ultimately to describe as one of the most valuable ''science-forming ideas.''<ref>{{cite book| editor=Niven, W.D. | title=The Scientific Papers of James Clerk Maxwell, 2 vols | location=New York | publisher=Dover | year=1965 | volume= 2|page=301 }}</ref>

=== Cambridge ===
William's father was able to make a generous provision for his favourite son's education and, in 1841, installed him, with extensive letters of introduction and ample accommodation, at Peterhouse, Cambridge.  While at Cambridge, Thomson was active in sports, athletics and sculling, winning the Colquhoun Sculls in 1843.<ref>{{cite book |last1=Mayer |first1=Roland |title=Peterhouse Boat Club 1828–1978 |year=1978 |publisher=Peterhouse Boat Club |isbn=0-9506181-0-1 |page=5}}</ref> He also took a lively interest in the classics, music, and literature; but the real love of his intellectual life was the pursuit of science. The study of [[Mathematics|mathematics]], physics, and in particular, of electricity, had captivated his imagination. In 1845 Thomson graduated as Second Wrangler.<ref>{{acad|id=THN841W|name=Thomson, William}}</ref> He also won the First Smith's Prize, which, unlike the tripos, is a test of original research. Robert Leslie Ellis, one of the examiners, is said to have declared to another examiner "You and I are just about fit to mend his pens."<ref>>{{cite book|last=Thompson|first=Silvanus |title=The Life of William Thomson, Baron Kelvin of Largs|volume= 1|year=1910|publisher=MacMillan and Co., Limited |page=98|url=https://archive.org/details/b31360403_0001}}</ref>

In 1845, he gave the first mathematical development of [[Biography:Michael Faraday|Michael Faraday]]'s idea that electric induction takes place through an intervening medium, or "dielectric", and not by some incomprehensible "action at a distance". He also devised the mathematical technique of electrical images, which became a powerful agent in solving problems of electrostatics, the science which deals with the forces between electrically charged bodies at rest. It was partly in response to his encouragement that Faraday undertook the research in September 1845 that led to the discovery of the [[Physics:Faraday effect|Faraday effect]], which established that light and magnetic (and thus electric) phenomena were related.

He was elected a fellow of St. Peter's (as Peterhouse was often called at the time) in June 1845.<ref name="physicsworld">{{cite news|first=Mark|last=McCartney|title=William Thomson: king of Victorian physics|work=Physics World|url=http://physicsworld.com/cws/article/print/16484|date=1 December 2002|access-date=16 July 2008|archive-date=15 July 2008|archive-url=https://web.archive.org/web/20080715173557/http://physicsworld.com/cws/article/print/16484|url-status=dead}}</ref> On gaining the fellowship, he spent some time in the laboratory of the celebrated [[Biography:Henri Victor Regnault|Henri Victor Regnault]], at Paris; but in 1846 he was appointed to the chair of natural philosophy in the [[Organization:University of Glasgow|University of Glasgow]]. At twenty-two he found himself wearing the gown of a professor in one of the oldest Universities in the country, and lecturing to the class of which he was a first year student a few years before.

=== Thermodynamics ===
By 1847, Thomson had already gained a reputation as a precocious and maverick scientist when he attended the British Association for the Advancement of Science annual meeting in Oxford. At that meeting, he heard [[Biography:James Prescott Joule|James Prescott Joule]] making yet another of his, so far, ineffective attempts to discredit the [[Physics:Caloric theory|caloric theory]] of heat and the theory of the [[Physics:Heat engine|heat engine]] built upon it by [[Biography:Nicolas Léonard Sadi Carnot|Sadi Carnot]] and [[Biography:Émile Clapeyron|Émile Clapeyron]]. Joule argued for the mutual convertibility of heat and mechanical work and for their mechanical equivalence.

Thomson was intrigued but sceptical. Though he felt that Joule's results demanded theoretical explanation, he retreated into an even deeper commitment to the Carnot–Clapeyron school. He predicted that the [[Physics:Melting point|melting point]] of ice must fall with [[Physics:Pressure|pressure]], otherwise its expansion on freezing could be exploited in a ''[[Unsolved:Perpetual motion|perpetuum mobile]]''. Experimental confirmation in his laboratory did much to bolster his beliefs.

In 1848, he extended the Carnot–Clapeyron theory further through his dissatisfaction that the [[Physics:Gas thermometer|gas thermometer]] provided only an [[Philosophy:Operational definition|operational definition]] of temperature. He proposed an ''[[Physics:Absolute temperature|absolute temperature]] scale''<ref>{{cite book | author=Chang, H. | title=Inventing Temperature: Measurement and Scientific Progress | publisher=Oxford University Press | year=2004 | isbn=978-0-19-517127-3|chapter =4 }}</ref> in which "a unit of heat descending from a body A at the temperature ''T''° of this scale, to a body B at the temperature (''T''−1)°, would give out the same mechanical effect ''[work]'', whatever be the number ''T''." Such a scale would be "quite independent of the physical properties of any specific substance."<ref>{{cite book | title=Mathematical and Physical Papers | chapter=On an Absolute Thermometric Scale founded on Carnot's Theory of the Motive Power of Heat, and calculated from Regnault's observations | publisher=Cambridge University Press | date=1848 | doi=10.1017/cbo9780511996009.040 | pages=100–106 | author = Thomson, W.| isbn=978-1-108-02898-1 }}</ref> By employing such a "waterfall", Thomson postulated that a point would be reached at which no further heat (caloric) could be transferred, the point of ''[[Physics:Absolute zero|absolute zero]]'' about which [[Biography:Guillaume Amontons|Guillaume Amontons]] had speculated in 1702. "Reflections on the Motive Power of Heat", published by Carnot in French in 1824, the year of Lord Kelvin's birth, used −267 as an estimate of the absolute zero temperature. Thomson used data published by Regnault to [[Calibration|calibrate]] his scale against established measurements.

In his publication, Thomson wrote:

{{Quotation|... The conversion of heat (or ''caloric'') into mechanical effect is probably impossible, certainly undiscovered}}—But a footnote signalled his first doubts about the caloric theory, referring to Joule's ''very remarkable discoveries''. Surprisingly, Thomson did not send Joule a copy of his paper, but when Joule eventually read it he wrote to Thomson on 6 October, claiming that his studies had demonstrated conversion of heat into work but that he was planning further experiments. Thomson replied on 27 October, revealing that he was planning his own experiments and hoping for a reconciliation of their two views.

Thomson returned to critique Carnot's original publication and read his analysis to the Royal Society of Edinburgh in January 1849,<ref>{{cite book | title=Mathematical and Physical Papers | chapter=An Account of Carnot's Theory of the Motive Power of Heat; with Numerical Results deduced from Regnault's Experiments on Steam | publisher=Cambridge University Press | date=1849 | doi=10.1017/cbo9780511996009.042 | pages=113–164 | author = Thomson, W.| isbn=978-1-108-02898-1 | url=https://zenodo.org/record/1634618 }}</ref> still convinced that the theory was fundamentally sound. However, though Thomson conducted no new experiments, over the next two years he became increasingly dissatisfied with Carnot's theory and convinced of Joule's. In February 1851 he sat down to articulate his new thinking. He was uncertain of how to frame his theory and the paper went through several drafts before he settled on an attempt to reconcile Carnot and Joule. During his rewriting, he seems to have considered ideas that would subsequently give rise to the [[Physics:Second law of thermodynamics|second law of thermodynamics]]. In Carnot's theory, lost heat was ''absolutely lost'' but Thomson contended that it was "''lost to man'' irrecoverably; but not lost in the material world". Moreover, his [[Religion:Theology|theological]] beliefs led Thompson to [[Extrapolation|extrapolate]] the second law to the cosmos, originating the idea of [[Astronomy:Heat death of the universe|universal heat death]].

{{Quotation|I believe the tendency in the material world is for motion to become diffused, and that as a whole the reverse of concentration is gradually going on – I believe that no physical action can ever restore the heat emitted from the Sun, and that this source is not inexhaustible; also that the motions of the Earth and other planets are losing ''[[Physics:Vis viva|vis viva]]'' which is converted into heat; and that although some ''vis viva'' may be restored for instance to the earth by heat received from the sun, or by other means, that the loss cannot be ''precisely'' compensated and I think it probable that it is under-compensated.<ref name="Sharlin 1979">Sharlin, p. 112</ref>}}

Compensation would require ''a creative act or an act possessing similar power'',<ref name="Sharlin 1979" /> resulting in a ''rejuvenating universe'' (as Thompson had previously compared universal heat death to a clock running slower and slower, although he was unsure whether it would eventually reach [[Physics:Thermodynamic equilibrium|thermodynamic equilibrium]] and ''stop for ever'').<ref>{{cite magazine |last1=Otis |first=Laura |year=2002 |title=Literature and Science in the Nineteenth Century: An Anthology |url= https://oxfordworldsclassics.com/view/10.1093/owc/9780199554652.001.0001/isbn-9780199554652 |magazine=OUP Oxford |volume=1 |pages=60–67}}</ref> Kelvin also formulated the [[Astronomy:Heat death paradox|heat death paradox]] (Kelvin’s paradox) in 1862, which uses the second law of thermodynamics to disprove the possibility of an infinitely old universe; this paradox was later extended by Rankine.<ref>{{cite magazine |last1=Thomson |first=William |year=1862 |title=On the Age of the Sun's Heat |url=https://zapatopi.net/kelvin/papers/on_the_age_of_the_suns_heat.html |magazine=Macmillan's Magazine |volume=5 |pages=388–393}}</ref>

In final publication, Thomson retreated from a radical departure and declared "the whole theory of the motive power of heat is founded on ... two ... propositions, due respectively to Joule, and to Carnot and Clausius."<ref>{{cite book | title=Mathematical and Physical Papers | chapter=On the dynamical theory of heat; with numerical results deduced from Mr. Joule's equivalent of a thermal unit and M. Regnault's observations on steam | publisher=Cambridge University Press | date=1852 | author = Thomson, W. | doi=10.1017/cbo9780511996009.049 | pages=174–332| isbn=978-1-108-02898-1 }}</ref> Thomson went on to state a form of the second law:

{{Quotation|It is impossible, by means of inanimate material agency, to derive mechanical effect from any portion of matter by cooling it below the temperature of the coldest of the surrounding objects.<ref>{{cite journal|last=Thomson|first=W.|title=On the Dynamical Theory of Heat, with numerical results deduced from Mr Joule's equivalent of a Thermal Unit, and M. Regnault's Observations on Steam|journal=Transactions of the Royal Society of Edinburgh|date=March 1851|volume=XX|issue=part II|pages=261–268; 289–298}} Also published in {{cite journal|last=Thomson|first=W.|title=On the Dynamical Theory of Heat, with numerical results deduced from Mr Joule's equivalent of a Thermal Unit, and M. Regnault's Observations on Steam|journal=Phil. Mag. |date=December 1852 |volume=IV |series=4 |issue=22 |pages=8–21 |url=https://archive.org/details/londonedinburghp04maga }}</ref>}}

In the paper, Thomson supported the theory that heat was a form of motion but admitted that he had been influenced only by the thought of Sir [[Biography:Humphry Davy|Humphry Davy]] and the experiments of Joule and Julius Robert von Mayer, maintaining that experimental demonstration of the conversion of heat into work was still outstanding.<ref>Thomson, W. (1851) ''p.''183</ref>

As soon as Joule read the paper he wrote to Thomson with his comments and questions. Thus began a fruitful, though largely epistolary, collaboration between the two men, Joule conducting experiments, Thomson analysing the results and suggesting further experiments. The collaboration lasted from 1852 to 1856, its discoveries including the [[Physics:Joule–Thomson effect|Joule–Thomson effect]], sometimes called the Kelvin–Joule effect, and the published results<ref>{{cite book | title=Mathematical and Physical Papers | chapter=On the thermal effects of fluids in motion | publisher=Cambridge University Press | date=2011-06-30 | doi=10.1017/cbo9780511996009.050 | pages=333–455| author1 = Joule, J. P. | author2 = Thomson, W.}}</ref> did much to bring about general acceptance of Joule's work and the [[Physics:Kinetic theory of gases|kinetic theory]].

Thomson published more than 650 scientific papers<ref name="britannica.com" /> and applied for 70 patents (not all were issued). Regarding science, Thomson wrote the following:

{{Quotation|In physical science a first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it.  I often say that when you can measure what you are speaking about and express it in numbers you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of ''science'', whatever the matter may be.<ref>{{cite book|last=Thomson|first=W.|title=Popular Lectures and Addresses, Vol. I|year=1891|publisher=MacMillan|location=London|page=80|isbn=978-0-598-77599-3|url=https://www.google.com/books?id=JcMKAAAAIAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false|access-date=25 June 2012}}</ref>  }}

== Transatlantic cable ==
=== Calculations on data rate ===
{{hatnote|To understand the technical issues in which Thomson became involved, see [[Engineering:Submarine communications cable#Bandwidth problems|Submarine communications cable: Bandwidth problems]].}}
Though now eminent in the academic field, Thomson was obscure to the general public. In September 1852, he married childhood sweetheart Margaret Crum, daughter of Walter Crum;<ref name=":0">{{ODNBweb|id=36507|title=Thomson, William|first=Crosbie|last=Smith}}</ref> but her health broke down on their honeymoon, and over the next 17 years, Thomson was distracted by her suffering. On 16 October 1854, George Gabriel Stokes wrote to Thomson to try to re-interest him in work by asking his opinion on some experiments of [[Biography:Michael Faraday|Michael Faraday]] on the proposed [[History:Transatlantic telegraph cable|transatlantic telegraph cable]].

Faraday had demonstrated how the construction of a cable would limit the rate at which messages could be sent – in modern terms, the [[Bandwidth (computing)|bandwidth]]. Thomson jumped at the problem and published his response that month.<ref>{{cite book | title=Mathematical and Physical Papers | chapter=On the theory of the electric telegraph | publisher=Cambridge University Press | date=1855 | doi=10.1017/cbo9780511996016.009 | pages=61–76| author = Thomson, W.| isbn=978-1-108-02899-8 }}</ref> He expressed his results in terms of the data rate that could be achieved and the economic consequences in terms of the potential [[Finance:Revenue|revenue]] of the transatlantic undertaking. In a further 1855 analysis,<ref>{{cite book| title=Mathematical and Physical Papers | chapter=On Peristaltic Induction of Electric Currents| publisher=Cambridge University Press | date=1855 | doi=10.1017/cbo9780511996016.011 | pages=77–91 [87]| author = Thomson, W.}}</ref> Thomson stressed the impact that the design of the cable would have on its [[Finance:Profit (accounting)|profitability]].

Thomson contended that the signalling speed through a given cable was inversely proportional to the [[Square (algebra)|square]] of the length of the cable. Thomson's results were disputed at a meeting of the British Association in 1856 by Wildman Whitehouse, the [[Physics:Electrician|electrician]] of the Atlantic Telegraph Company. Whitehouse had possibly misinterpreted the results of his own experiments but was doubtless feeling financial pressure as plans for the cable were already well under way. He believed that Thomson's calculations implied that the cable must be "abandoned as being practically and commercially impossible".

Thomson attacked Whitehouse's contention in a letter to the popular ''Athenaeum'' magazine,<ref>{{cite book | author = Thomson, W.| title=Mathematical and Physical Papers | chapter=Letters on "telegraphs to America" | publisher=Cambridge University Press | date=1856 | doi=10.1017/cbo9780511996016.012 | pages=92–102| isbn=978-1-108-02899-8 }}</ref> pitching himself into the public eye. Thomson recommended a larger conductor with a larger [[Cross section (geometry)|cross section]] of insulation. He thought Whitehouse no fool, and suspected that he might have the practical skill to make the existing design work. Thomson's work had attracted the attention of the project's undertakers. In December 1856, he was elected to the board of directors of the Atlantic Telegraph Company.

=== Scientist to engineer ===
Thomson became scientific adviser to a team with Whitehouse as chief electrician and Sir Charles Tilston Bright as chief engineer but Whitehouse had his way with the specification, supported by Faraday and Samuel F. B. Morse.

[[File:Sir William Thomson's telegraphic syphon recorder.jpg|thumb|upright|William Thomson's telegraphic syphon recorder, on display at Porthcurno Telegraph Museum, in January 2019.]]

Thomson sailed on board the cable-laying ship {{HMS|Agamemnon|1852|6}} in August 1857, with Whitehouse confined to land owing to illness, but the voyage ended after {{convert|380|mi|km}} when the cable parted. Thomson contributed to the effort by publishing in the ''Engineer'' the whole theory of the [[Physics:Stress|stresses]] involved in the laying of a submarine [[Engineering:Submarine communications cable|cable]], and showed that when the line is running out of the ship, at a constant speed, in a uniform depth of water, it sinks in a slant or straight incline from the point where it enters the water to that where it touches the bottom.<ref>{{cite book | title=Mathematical and Physical Papers | chapter=On the forces concerned in the laying and lifting of deep-sea cables| publisher=Cambridge University Press | date=1865 | doi=10.1017/cbo9780511996016.020 | pages=153–167 | author = Thomson, W.| isbn=978-1-108-02899-8}}</ref>

Thomson developed a complete system for operating a submarine telegraph that was capable of sending a [[Character (computing)|character]] every 3.5&nbsp;seconds. He patented the key elements of his system, the [[Physics:Mirror galvanometer|mirror galvanometer]] and the siphon recorder, in 1858.

Whitehouse still felt able to ignore Thomson's many suggestions and proposals. It was not until Thomson convinced the board that using purer copper for replacing the lost section of cable would improve data capacity, that he first made a difference to the execution of the project.<ref>Sharlin, p. 141</ref>

The board insisted that Thomson join the 1858 cable-laying expedition, without any financial compensation, and take an active part in the project. In return, Thomson secured a trial for his mirror galvanometer, which the board had been unenthusiastic about, alongside Whitehouse's equipment. Thomson found the access he was given unsatisfactory and the ''Agamemnon'' had to return home following the disastrous storm of June 1858. In London, the board was about to abandon the project and mitigate their losses by selling the cable. Thomson, Cyrus West Field and Curtis M. Lampson argued for another attempt and prevailed, Thomson insisting that the technical problems were tractable. Though employed in an advisory capacity, Thomson had, during the voyages, developed a real engineer's instincts and skill at practical problem-solving under pressure, often taking the lead in dealing with emergencies and being unafraid to assist in manual work. A cable was completed on 5 August.

=== Disaster and triumph ===
Thomson's fears were realized when Whitehouse's apparatus proved insufficiently sensitive and had to be replaced by Thomson's mirror galvanometer. Whitehouse continued to maintain that it was his equipment that was providing the service and started to engage in desperate measures to remedy some of the problems. He succeeded in fatally damaging the cable by applying 2,000&nbsp;[[Volt|V]]. When the cable failed completely Whitehouse was dismissed, though Thomson objected and was reprimanded by the board for his interference. Thomson subsequently regretted that he had acquiesced too readily to many of Whitehouse's proposals and had not challenged him with sufficient vigour.<ref>Sharlin, p. 144</ref>

A joint committee of inquiry was established by the Board of Trade and the Atlantic Telegraph Company. Most of the blame for the cable's failure was found to rest with Whitehouse.<ref>"Board of Trade Committee to Inquire into … Submarine Telegraph Cables', Parl. papers (1860), 52.591, no. 2744</ref> The committee found that, though underwater cables were notorious in their lack of [[Reliability engineering|reliability]], most of the problems arose from known and avoidable causes. Thomson was appointed one of a five-member committee to recommend a specification for a new cable. The committee reported in October 1863.<ref>"Report of the Scientific Committee Appointed to Consider the Best Form of Cable for Submersion Between Europe and America" (1863)</ref>

In July 1865, Thomson sailed on the cable-laying expedition of the {{SS|Great Eastern}} but the voyage was dogged by technical problems. The cable was lost after {{convert|1200|mi|km}} had been laid and the project was abandoned. A further attempt in 1866 laid a new cable in two weeks, and then recovered and completed the 1865 cable. The enterprise was now feted as a triumph by the public and Thomson enjoyed a large share of the adulation. Thomson, along with the other principals of the project, was knighted on 10 November 1866.

To exploit his inventions for signalling on long submarine cables, Thomson now entered into a partnership with [[Biography:C. F. Varley|C. F. Varley]] and Fleeming Jenkin. In conjunction with the latter, he also devised an automatic curb sender, a kind of [[Engineering:Telegraph key|telegraph key]] for sending messages on a cable.

=== Later expeditions ===
Thomson took part in the laying of the French Atlantic [[Engineering:Submarine communications cable|submarine communications cable]] of 1869, and with Jenkin was engineer of the Western and Brazilian and Platino-Brazilian cables, assisted by vacation student James Alfred Ewing. He was present at the laying of the Pará to Pernambuco section of the Brazilian coast cables in 1873.

Thomson's wife, Margaret, died on 17 June 1870, and he resolved to make changes in his life. Already addicted to seafaring, in September he purchased a 126-ton [[Engineering:Schooner|schooner]], the ''Lalla Rookh''<ref>{{cite book |author=Gurney, Alan |date=2005 |chapter=Chapter 19: Thomson's Compass and Binnacle |title=Compass: A Story of Exploration and Innovation |publisher=W. W. Norton & Company |isbn=978-0-393-60883-0 }}</ref><ref>{{cite web |url=https://www.diomedia.com/stock-photo-lord-kelvins-sailing-yacht-lalla-rookh-c-1860-1900-image5525313.html |title=Lord Kelvin's sailing yacht 'Lalla Rookh', c 1860–1900 |website=stock images}}</ref> and used it as a base for entertaining friends and scientific colleagues. His maritime interests continued in 1871 when he was appointed to the Board of Enquiry into the sinking of {{HMS|Captain|1869|6}}.

In June 1873, Thomson and Jenkin were on board the ''Hooper'', bound for [[Place:Lisbon|Lisbon]] with {{convert|2500|mi|km|-1}} of cable when the cable developed a fault. An unscheduled 16-day stop-over in Madeira followed and Thomson became good friends with Charles R. Blandy and his three daughters. On 2 May 1874 he set sail for Madeira on the ''Lalla Rookh''. As he approached the harbour, he signalled to the Blandy residence "Will you marry me?" and Fanny (Blandy's daughter Frances Anna Blandy) signalled back "Yes". Thomson married Fanny, 13 years his junior, on 24 June 1874.
[[File:Hubert von Herkomer03.jpg|thumb|upright|Lord Kelvin by Hubert von Herkomer]]

== Other contributions ==
=== Thomson and Tait: ''Treatise on Natural Philosophy'' ===
{{Main|Physics:Treatise on Natural Philosophy}}
Over the period 1855 to 1867, Thomson collaborated with Peter Guthrie Tait on a text book that founded the study of [[Physics:Mechanics|mechanics]] first on the mathematics of [[Physics:Kinematics|kinematics]], the description of motion without regard to [[Physics:Force|force]]. The text developed [[Physics:Dynamics (mechanics)|dynamics]] in various areas but with constant attention to [[Physics:Energy|energy]] as a unifying principle.

A second edition appeared in 1879, expanded to two separately bound parts. The textbook set a standard for early education in [[Physics:Mathematical physics|mathematical physics]].

=== Atmospheric electricity ===
Kelvin made significant contributions to [[Physics:Atmospheric electricity|atmospheric electricity]] for the relatively short time for which he worked on the subject, around 1859.<ref name=":1">{{Cite journal|last1=Aplin|first1=K. L.|last2=Harrison|first2=R. G.|date=2013-09-03|title=Lord Kelvin's atmospheric electricity measurements|journal=History of Geo- and Space Sciences|volume=4|issue=2|pages=83–95|doi=10.5194/hgss-4-83-2013|arxiv=1305.5347|bibcode=2013HGSS....4...83A|s2cid=9783512}}</ref> He developed several instruments for measuring the atmospheric electric field, using some of the electrometers he had initially developed for telegraph work, which he tested at Glasgow and whilst on holiday on Arran. His measurements on Arran were sufficiently rigorous and well-calibrated that they could be used to deduce air pollution from the Glasgow area, through its effects on the atmospheric electric field.<ref>{{Cite journal|last=Aplin|first=Karen L.|date=April 2012|title=Smoke emissions from industrial western Scotland in 1859 inferred from Lord Kelvin's atmospheric electricity measurements|journal=Atmospheric Environment|volume=50|pages=373–376|doi=10.1016/j.atmosenv.2011.12.053|bibcode=2012AtmEn..50..373A}}</ref> Kelvin's water dropper electrometer was used for measuring the atmospheric electric field at [[Organization:King's Observatory|Kew Observatory]] and [[Organization:Eskdalemuir Observatory|Eskdalemuir Observatory]] for many years,<ref>{{Cite journal|last=Harrison|first=R. G.|date=2003|title=Twentieth-century atmospheric electrical measurements at the observatories of Kew, Eskdalemuir and Lerwick|journal=Weather|volume=58|issue=1|pages=11–19|doi=10.1256/wea.239.01|bibcode=2003Wthr...58...11H|s2cid=122673748 }}</ref> and one was still in use operationally at the Kakioka Observatory in Japan<ref>{{Cite journal|last1=Takeda|first1=M.|last2=Yamauchi|first2=M.|last3=Makino|first3=M.|last4=Owada|first4=T.|date=2011|title=Initial effect of the Fukushima accident on atmospheric electricity|journal=Geophysical Research Letters|volume=38|issue=15|doi=10.1029/2011GL048511|bibcode=2011GeoRL..3815811T|s2cid=73530372 }}</ref> until early 2021. Kelvin may have unwittingly observed atmospheric electrical effects caused by the Carrington event (a significant geomagnetic storm) in early September 1859.<ref name=":1" />

=== Kelvin's vortex theory of the atom ===
{{Main|Vortex theory of the atom}}

Between 1870 and 1890 the vortex atom theory, which purported that an [[Physics:Atom|atom]] was a [[Vortex|vortex]] in the [[Physics:Luminiferous aether|aether]], was popular among British physicists and mathematicians. Thomson pioneered the theory, which was distinct from the seventeenth century vortex theory of Descartes in that Thomson was thinking in terms of a unitary continuum theory, whereas Descartes was thinking in terms of three different types of matter, each relating respectively to emission, transmission, and reflection of light.<ref name="Kragh">{{cite journal |last1=Kragh |first1=Helge |title=The Vortex Atom: A Victorian Theory of Everything |journal=Centaurus |date=2002 |volume=44 |issue=1–2 |pages=32–114 |url=https://www.academia.edu/4084776 |access-date=9 March 2019 |doi=10.1034/j.1600-0498.2002.440102.x }}</ref> About 60 scientific papers were written by approximately 25 scientists. Following the lead of Thomson and Tait,<ref>{{cite journal | last1 = Thomson | first1 = Wm. | year = 1867 | title = On Vortex Atoms | url = http://zapatopi.net/kelvin/papers/on_vortex_atoms.html | journal = Proceedings of the Royal Society of Edinburgh | volume = 6 | pages = 94–105 | doi = 10.1017/S0370164600045430 }}</ref> the branch of [[Topology|topology]] called [[Knot theory|knot theory]] was developed. Kelvin's initiative in this complex study that continues to inspire new mathematics has led to persistence of the topic in [[History:History of science|history of science]].<ref>{{cite journal|author=Silliman, Robert H. |year=1963|title=William Thomson: Smoke Rings and Nineteenth-Century Atomism|journal=Isis|volume=54|issue=4|pages=461–474|doi=10.1086/349764 |jstor=228151|s2cid=144988108 }}</ref>

=== Marine ===
[[File:DSCN1739-thomson-tide-machine.jpg|thumb|right|upright|Thomson's [[Tide-predicting machine|tide-predicting machine]]]]
Thomson was an enthusiastic yachtsman, his interest in all things relating to the sea perhaps arising from, or fostered by, his experiences on the ''Agamemnon'' and the ''[[Engineering:SS Great Eastern|Great Eastern]]''.

Thomson introduced a method of deep-sea [[Depth sounding|depth sounding]], in which a steel piano wire replaces the ordinary hand line. The wire glides so easily to the bottom that "flying soundings" can be taken while the ship is at full speed. A pressure gauge to register the depth of the sinker was added by Thomson.

About the same time he revived the Sumner method of finding a ship's position, and calculated a set of tables for its ready application.

During the 1880s, Thomson worked to perfect the adjustable [[Physics:Compass|compass]] to correct errors arising from [[Magnetic deviation|magnetic deviation]] owing to the increased use of iron in [[Engineering:Naval architecture|naval architecture]]. Thomson's design was a great improvement on the older instruments, being steadier and less hampered by friction. The deviation due to the ship's magnetism was corrected by movable iron masses at the [[Engineering:Binnacle|binnacle]]. Thomson's innovations involved much detailed work to develop principles identified by George Biddell Airy and others, but contributed little in terms of novel physical thinking. Thomson's energetic lobbying and networking proved effective in gaining acceptance of his instrument by The Admiralty.

[[File:Sir Lord Kelvin Mariner's Compass with Sun Dial.jpg|thumb|right|Kelvin Mariner's Compass]]

{{quotation | Scientific biographers of Thomson, if they have paid any attention at all to his compass innovations, have generally taken the matter to be a sorry saga of dim-witted naval administrators resisting marvellous innovations from a superlative scientific mind. Writers sympathetic to the Navy, on the other hand, portray Thomson as a man of undoubted talent and enthusiasm, with some genuine knowledge of the sea, who managed to parlay a handful of modest ideas in compass design into a commercial monopoly for his own manufacturing concern, using his reputation as a bludgeon in the law courts to beat down even small claims of originality from others, and persuading the Admiralty and the law to overlook both the deficiencies of his own design and the virtues of his competitors'.
<br />
The truth, inevitably, seems to lie somewhere between the two extremes.<ref>Lindley, p. 259</ref> }}

Charles Babbage had been among the first to suggest that a [[Lighthouse|lighthouse]] might be made to signal a distinctive number by occultations of its light, but Thomson pointed out the merits of the [[Engineering:Morse code|Morse code]] for the purpose, and urged that the signals should consist of short and long flashes of the light to represent the dots and dashes.

=== Electrical standards ===
Thomson did more than any other electrician up to his time in introducing accurate methods and apparatus for measuring electricity. As early as 1845 he pointed out that the experimental results of William Snow Harris were in accordance with the laws of [[Biography:Charles-Augustin de Coulomb|Coulomb]]. In the ''Memoirs of the Roman Academy of Sciences'' for 1857 he published a description of his new divided ring [[Physics:Electrometer|electrometer]], based on the old electroscope of Johann Gottlieb Friedrich von Bohnenberger and he introduced a chain or series of effective instruments, including the quadrant electrometer, which cover the entire field of electrostatic measurement. He invented the current balance, also known as the ''Kelvin balance'' or ''Ampere balance'' (''SiC''), for the [[Accuracy and precision|precise]] specification of the [[Ampere|ampere]], the standard unit of [[Physics:Electric current|electric current]]. From around 1880 he was aided by the electrical engineer Magnus Maclean FRSE in his electrical experiments.<ref>{{cite web|title=Maclean, Magnus, 1857–1937, electrical engineer |url=http://strathclyde.ica-atom.org/maclean-magnus-1857-1937-electrical-engineer |website=University of Strathclyde Archives |access-date=2018-01-19}}</ref>

In 1893, Thomson headed an international commission to decide on the design of the Niagara Falls [[Chemistry:Power station|power station]]. Despite his belief in the superiority of [[Physics:Direct current|direct current]] [[Finance:Electric power transmission|electric power transmission]], he endorsed Westinghouse's [[Physics:Alternating current|alternating current]] system which had been demonstrated at the Chicago World's Fair of that year. Even after Niagara Falls Thomson still held to his belief that direct current was the superior system.<ref>Lindley, p. 293</ref>

Acknowledging his contribution to electrical standardisation, the [[Organization:International Electrotechnical Commission|International Electrotechnical Commission]] elected Thomson as its first President at its preliminary meeting, held in London on 26–27 June 1906. "On the proposal of the President [Mr Alexander Siemens, Great Britain], secounded [sic] by Mr Mailloux [US Institute of Electrical Engineers] the Right Honorable Lord Kelvin, G.C.V.O., O.M., was unanimously elected first President of the Commission", minutes of the Preliminary Meeting Report read.<ref>{{cite web | url=http://www.iec.ch/about/history/documents/pdf/IEC_Founding_Meeting_Report_1906.pdf | title=1906 Preliminary Meeting Report, pp 46–48 | website=The minutes from our first meeting | author=IEC | access-date=21 October 2012 | archive-date=2 May 2019 | archive-url=https://web.archive.org/web/20190502223234/https://www.iec.ch/about/history/documents/pdf/IEC_Founding_Meeting_Report_1906.pdf | url-status=dead }}</ref>

=== Age of the Earth: geology ===
[[File:Lord Kelvin Vanity Fair 1897-04-29.jpg|left|thumb|upright|Kelvin caricatured by Spy for ''Vanity Fair'', 1897]]

Kelvin made an early physics-based estimation of the [[Earth:Age of the Earth|age of the Earth]]. Given his youthful work on the figure of the Earth and his interest in heat conduction, it is no surprise that he chose to investigate the Earth's cooling and to make historical inferences of the Earth's age from his calculations. Thomson was a [[Philosophy:Creationism|creationist]] in a broad sense, but he was not a '[[Unsolved:Flood geology|flood geologist]]'<ref>Sharlin, p. 169</ref> (a view that had [[Unsolved:Flood geology#Criticisms and retractions: the downfall of Diluvialism|lost mainstream scientific support]] by the 1840s.<ref>{{cite book| last1 = Imbrie| first1 = John| first2 = Katherine Palmer| last2 = Imbrie| title = Ice ages: solving the mystery| year = 1986| publisher = Harvard University Press| place = Cambridge, Mass.| isbn = 978-0-674-44075-3| page =40| url = https://archive.org/details/iceagessolvingmy0000imbr_w0f3/page/40}}</ref><ref>{{Cite book  | last1 = Young | first1 = Davis A. | last2 = Stearley | first2 = Ralph F. | title = The Bible, rocks, and time : geological evidence for the age of the earth | year = 2008 | publisher = IVP Academic | location = Downers Grove, Ill. | isbn = 978-0-8308-2876-0|page=99}}</ref> He contended that the [[Physics:Laws of thermodynamics|laws of thermodynamics]] operated from the birth of the universe and envisaged a dynamic process that saw the organisation and evolution of the [[Astronomy:Solar System|Solar System]] and other structures, followed by a gradual "heat death". He developed the view that the Earth had once been too hot to support life and contrasted this view with that of uniformitarianism, that conditions had remained constant since the indefinite past. He contended that "This earth, certainly a moderate number of millions of years ago, was a red-hot globe … ."<ref name=Burchfield />

After the publication of [[Biography:Charles Darwin|Charles Darwin]]'s ''On the Origin of Species'' in 1859, Thomson saw evidence of the relatively short habitable age of the Earth as tending to contradict Darwin's gradualist explanation of slow [[Biology:Natural selection|natural selection]] bringing about biological diversity. Thomson's own views favoured a version of [[Religion:Theistic evolution|theistic evolution]] sped up by divine guidance.<ref>{{cite book |author=Bowler, Peter J. |title=The eclipse of Darwinism: anti-Darwinian evolution theories in the decades around 1900 |edition=paperback |publisher=Johns Hopkins University Press |location=Baltimore |year=1983 |pages=23–24 |isbn=978-0-8018-4391-4 }}</ref> His calculations showed that the Sun could not have possibly existed long enough to allow the slow incremental development by [[Biology:Evolution|evolution]] – unless it was heated by an energy source beyond the knowledge of [[History:Victorian era|Victorian era]] science. He was soon drawn into public disagreement with geologists and with Darwin's supporters [[Biography:John Tyndall|John Tyndall]] and T. H. Huxley. In his response to Huxley's address to the Geological Society of London (1868) he presented his address "Of Geological Dynamics" (1869)<ref>{{cite web |title="Of Geological Dynamics" excerpts |url=http://zapatopi.net/kelvin/papers/of_geological_dynamics.html |access-date=29 October 2011 |publisher=Zapatopi.net}}</ref> which, among his other writings, challenged the geologists' assertion that the earth must be vastly old, perhaps billions of years in age.<ref name="England et al 2007">Kelvin did pay off gentleman's bet with Strutt on the importance of radioactivity in the Earth. The Kelvin period does exist in the evolution of stars. They shine from gravitational energy for a while (correctly calculated by Kelvin) before fusion and the main sequence begins.  Fusion was not understood until well after Kelvin's time.
  {{cite journal |author1=England, P. |author2=Molnar, P. |author3=Righter, F. |date=January 2007 |title=John Perry's neglected critique of Kelvin's age for the Earth: A missed opportunity in geodynamics |journal=GSA Today |volume=17 |issue=1 |pages=4–9 |doi=10.1130/GSAT01701A.1 |doi-access=free}}</ref>

Thomson's initial 1864 estimate of the Earth's age was from 20 to 400 million years old. These wide limits were due to his uncertainty about the melting temperature of rock, to which he equated the Earth's interior temperature,<ref>Tung, K.K. (2007) ''Topics in Mathematical Modeling''. Princeton University Press. {{ISBN|
9780691116426}}. pp. 243–251. In Thomson's theory the Earth's age is proportional to the ''square'' of the difference between interior temperature and surface temperature, so that the uncertainty in the former leads to an even larger relative uncertainty in the age.</ref><ref>{{Cite journal|last=Thomson|first=William|title=On the Secular Cooling of the Earth|journal=Transactions of the Royal Society of Edinburgh|volume=XXIII|pages=160–161|doi=10.1017/s0080456800018512|year=1862|s2cid=126038615 |url=https://zenodo.org/record/2202654}}</ref> as well as the uncertainty in thermal conductivities and specific heats of rocks. Over the years he refined his arguments and reduced the upper bound by a factor of ten, and in 1897 Thomson, now Lord Kelvin, ultimately settled on an estimate that the Earth was 20–40&nbsp;million years old.<ref name=Burchfield>{{Cite book | last=Burchfield | first=Joe D. | title=Lord Kelvin and the Age of the Earth | year=1990 | publisher=University of Chicago Press | isbn=978-0-226-08043-7 | page=43 }}</ref><ref>{{Cite book | last=Hamblin | first=W. Kenneth | title=The Earth's Dynamic Systems 5th ed | year=1989 | publisher=Macmillan Publishing Company | isbn=978-0-02-349381-2 | page=[https://archive.org/details/earthsdynamicsys00hamb_1/page/135 135] | url=https://archive.org/details/earthsdynamicsys00hamb_1/page/135 }}</ref> In a letter published in Scientific American Supplement 1895 Kelvin criticized geologists' estimates of the age of rocks and the age of the earth, including the views published by [[Biography:Charles Darwin|Charles Darwin]], as "vaguely vast age".<ref>{{Cite journal|last=Heuel-Fabianek|first=Burkhard|title=Natürliche Radioisotope: die "Atomuhr" für die Bestimmung des absoluten Alters von Gesteinen und archäologischen Funden|url=https://www.researchgate.net/publication/315459191|journal=StrahlenschutzPraxis|volume=1/2017|pages=31–42}}</ref>

His exploration of this estimate can be found in his 1897 address to the Victoria Institute, given at the request of the Institute's president [[Biography:Sir George Stokes, 1st Baronet|George Stokes]],<ref>{{Cite journal|url=https://books.google.com/books?id=sSeKh7OWAcgC|page=1095|title=The life of Lord Kelvin|journal=American Journal of Physics|volume=45|issue=10|author=Thompson, Silvanus Phillips |isbn=978-0-8284-0292-7|date=January 1977|bibcode=1977AmJPh..45.1010T|doi=10.1119/1.10735}}</ref> as recorded in that Institute's journal ''[[Religion:Science and Christian Belief|Transactions]]''.<ref>{{Cite journal|url=https://books.google.com/books?id=sSeKh7OWAcgC|page=998|title=The life of Lord Kelvin|journal=American Journal of Physics|volume=45|issue=10|author=Thompson, Silvanus Phillips |isbn=978-0-8284-0292-7|date=January 1977|bibcode=1977AmJPh..45.1010T|doi=10.1119/1.10735}}</ref> Although his former assistant John Perry published a paper in 1895 challenging Kelvin's assumption of low [[Physics:Thermal conductivity|thermal conductivity]] inside the Earth, and thus showing a much greater age,<ref>Perry, John (1895) "On the age of the earth," ''Nature'', '''51''' :  [http://babel.hathitrust.org/cgi/pt?id=mdp.39015038750868;view=1up;seq=266 224–227], 341–342, 582–585. ([https://archive.org/stream/naturelo51londuoft#page/224/mode/2up 51:224], [https://archive.org/stream/naturelo51londuoft#page/340/mode/2up 51:341], [https://archive.org/stream/naturelo51londuoft#page/582/mode/2up 51:582] at Internet Archive)</ref> this had little immediate impact. The discovery in 1903 that [[Physics:Radioactive decay|radioactive decay]] releases heat led to Kelvin's estimate being challenged, and [[Biography:Ernest Rutherford|Ernest Rutherford]] famously made the argument in a 1904 lecture attended by Kelvin that this provided the unknown energy source Kelvin had suggested, but the estimate was not overturned until the development in 1907 of [[Physics:Radiometric dating|radiometric dating]] of rocks.<ref name="England et al 2007" />

The discovery of radioactivity largely invalidated Kelvin's estimate of the age of the Earth. Although he eventually paid off a gentleman's bet with Strutt on the importance of radioactivity in the Earth's geology, he never publicly acknowledged this because he thought he had a much stronger argument restricting the age of the Sun to no more than 20 million years. Without sunlight, there could be no explanation for the sediment record on the Earth's surface. At the time, the only known source for solar energy was [[Astronomy:Gravitational collapse|gravitational collapse]]. It was only when [[Physics:Thermonuclear fusion|thermonuclear fusion]] was recognised in the 1930s that Kelvin's age paradox was truly resolved.<ref>{{cite journal|last1=Stacey|first1=Frank D.|journal=[[Earth:Journal of Geophysical Research|Journal of Geophysical Research]]|volume=105|pages=13155–13158|year=2000|issue=B6|doi=10.1029/2000JB900028|title=Kelvin's age of the Earth paradox revisited|bibcode = 2000JGR...10513155S |doi-access=free}}</ref> However, modern cosmology recognizes the Kelvin period in the early life of a star, during which it shines from gravitational energy (correctly calculated by Kelvin) before fusion and the main sequence begins.
[[File:Jubilee of Baron Kelvin. Photograph by Maclure, Macdonald & Wellcome V0028635 (cropped).jpg|thumb|Kelvin on a pleasure cruise on the River Clyde aboard the steamer ''Glen Sannox'' for his 17 June 1896 "jubilee" as Professor of Natural Philosophy at Glasgow ]]
[[File:No-nb bldsa k2a001.jpg|thumb|Lord Kelvin and Lady Kelvin hosting Norwegians [[Biography:Fridtjof Nansen|Fridtjof Nansen]] and Eva Nansen visiting at their house in February 1897]]

== Later life and death ==
[[File:The Thomson family grave and memorial, Glasgow Necropolis.jpg|thumb|upright|The grave of the Thomson family, Glasgow Necropolis]]
In the winter of 1860–1861 Kelvin slipped on the ice while curling near his home at Netherhall and fractured his leg, causing him to miss the 1861 Manchester meeting of the British Association for the Advancement of Science, and to limp thereafter.<ref name=":0" /> He remained something of a celebrity on both sides of the Atlantic until his death.

Thomson remained a devout believer in [[Religion:Christianity|Christianity]] throughout his life; attendance at chapel was part of his daily routine.<ref>McCartney & Whitaker (2002), reproduced on [http://physicsweb.org/articles/world/15/12/6 Institute of Physics website]</ref> He saw his Christian faith as supporting and informing his scientific work, as is evident from his address to the annual meeting of the Christian Evidence Society,<ref>Thomson, W. (1889) Address to the Christian Evidence Society</ref> 23 May 1889.<ref>The Finality of this Globe, Hampshire Telegraph, 15 June 1889, p. 11.</ref>

In the 1902 Coronation Honours list published on 26 June 1902 (the original day of the coronation of Edward VII and Alexandra),<ref>{{Cite newspaper The Times |title=The Coronation Honours |date=26 June 1902 |page=5 |issue=36804}}</ref> Kelvin was appointed a Privy Councillor and one of the first members of the new Order of Merit (OM). He received the order from the King on 8 August 1902,<ref>{{Cite newspaper The Times |title=Court Circular |date=9 August 1902 |page=6 |issue=36842}}</ref><ref>{{London Gazette|issue=27470|page=5679|date=2 September 1902|}}</ref> and was sworn a member of the council at Buckingham Palace on 11 August 1902.<ref name="LG27464">{{London Gazette |issue=27464 |date=12 August 1902 |page=5173 }}</ref> In his later years he often travelled to his town house at 15 Eaton Place, off Eaton Square in London's Belgravia.<ref name=":0" />

In November 1907 he caught a chill and his condition deteriorated until he died at his Scottish country seat, Netherhall, in Largs on 17 December.<ref>"Death of Lord Kelvin". ''Times''</ref>

At the request of Westminster Abbey, the undertakers Wylie & Lochhead prepared an oak coffin, lined with lead. In the dark of the winter evening the cortege set off from Netherhall for Largs railway station, a distance of about a mile. Large crowds witnessed the passing of the cortege, and shopkeepers closed their premises and dimmed their lights. The coffin was placed in a special Midland and Glasgow and South Western Railway van. The train set off at 8.30 pm for Kilmarnock, where the van was attached to the overnight express to St Pancras railway station in London.<ref name="The Scotsman, 23 December 1907">The Scotsman, 23 December 1907</ref>

Kelvin's funeral was to be held on 23 December 1907.<ref name=":0" /> The coffin was taken from St Pancras by hearse to Westminster Abbey, where it rested overnight in St Faith's Chapel. The following day the Abbey was crowded for the funeral, including representatives from the [[Organization:University of Glasgow|University of Glasgow]] and the [[Organization:University of Cambridge|University of Cambridge]], along with representatives from France, Italy, Germany, [[Place:Austria-Hungary|Austria-Hungary]], Russia, the United States, Canada, Australia, Japan, and [[Place:Monaco|Monaco]]. Kelvin's grave is in the nave, near the choir screen, and close to the graves of [[Biography:Isaac Newton|Isaac Newton]], [[Biography:John Herschel|John Herschel]], and [[Biography:Charles Darwin|Charles Darwin]].<ref>Hall, Alfred Rupert (1966) ''The Abbey Scientists''. London: Roger & Robert Nicholson. p. 62.</ref> The pall-bearers included Darwin's son, Sir George Darwin.<ref>Glasgow Herald, 24 December 1907</ref>

Back in Scotland the University of Glasgow held a memorial service for Kelvin in the Bute Hall. Kelvin had been a member of the Scottish Episcopal Church, attached to St Columba's Episcopal Church in Largs, and when in Glasgow to St Mary's Episcopal Church (now, St Mary's Cathedral, Glasgow).<ref name="The Scotsman, 23 December 1907" /> At the same time as the funeral in Westminster Abbey, a service was held in St Columba's Episcopal Church, Largs, attended by a large congregation including burgh dignitaries.<ref>Glasgow Evening Times, 23 December 1907</ref>

William Thomson is also memorialised on the Thomson family grave in Glasgow Necropolis. The family grave has a second modern memorial to William alongside, erected by the Royal Philosophical Society of Glasgow; a society of which he was president in the periods 1856–1858 and 1874–1877.<ref>{{cite book | author=Royal Philosophical Society of Glasgow | title=No Mean Society: 200 years of the Royal Philosophical Society of Glasgow. 2nd Ed | year=2008 | page=138 | url=http://royalphil.org/Sessions/No%20Mean%20Society.pdf | isbn=978-0-9544965-0-0 }}</ref>

== Aftermath and legacy ==
=== Limits of classical physics ===
In 1884, Thomson led a master class on "Molecular Dynamics and the Wave Theory of Light" at [[Organization:Johns Hopkins University|Johns Hopkins University]].<ref>Kargon, Robert and Achinstein, Peter (1987) ''Kelvin's Baltimore Lectures and Modern Theoretical Physics: historical and philosophical perspectives''. MIT Press. {{ISBN|0-262-11117-9}}</ref> Kelvin referred to the [[Physics:Acoustic wave equation|acoustic wave equation]] describing sound as waves of pressure in air and attempted to describe also an [[Physics:Electromagnetic wave equation|electromagnetic wave equation]], presuming a [[Physics:Luminiferous aether|luminiferous aether]] susceptible to vibration. The study group included Michelson and Morley who subsequently performed the [[Physics:Michelson–Morley experiment|Michelson–Morley experiment]], which subsequently found no luminiferous aether. Thomson did not provide a text but A. S. Hathaway took notes and duplicated them with a [[Engineering:Mimeograph#Papyrograph|Papyrograph]]. As the subject matter was under active development, Thomson amended that text and in 1904 it was typeset and published. Thomson's attempts to provide mechanical models ultimately failed in the electromagnetic regime. Starting from his lecture in 1884, Kelvin was also the first scientist to formulate the hypothetical concept of [[Astronomy:Dark matter|dark matter]]; he then attempted to define and locate some "dark bodies" in the [[Astronomy:Milky Way|Milky Way]].<ref>{{cite web |url=https://cerncourier.com/a/how-dark-matter-became-a-particle/ |title=How dark matter became a particle  |publisher=CERN Courier |date=2017-04-13 |access-date=2022-03-16}}</ref><ref>{{cite web|url=https://ned.ipac.caltech.edu/level5/Sept16/Bertone/Bertone2.html|title=A History of Dark Matter- Gianfranco Bertone & Dan Hooper|website=ned.ipac.caltech.edu}}</ref>

On 27 April 1900 he gave a widely reported lecture titled ''Nineteenth-Century Clouds over the Dynamical Theory of Heat and Light'' to the Royal Institution.<ref>"Lord Kelvin, Nineteenth Century Clouds over the Dynamical Theory of Heat and Light", reproduced in ''Notices of the Proceedings at the Meetings of the Members of the Royal Institution of Great Britain with Abstracts of the Discourses'', Volume 16, [https://books.google.com/books?id=YvoAAAAAYAAJ&pg=PA363 p. 363–397]</ref><ref>''The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science'', Series 6, volume 2, pages 1–40 (1901)</ref> The two "dark clouds" he was alluding to were confusion surrounding how matter moves through the aether (including the puzzling results of the [[Physics:Michelson–Morley experiment|Michelson–Morley experiment]]) and indications that the [[Physics:Equipartition theorem|Law of Equipartition]] in statistical mechanics might break down. Two major physical theories were developed during the twentieth century starting from these issues: for the former, the [[Physics:Theory of relativity|theory of relativity]]; for the second, [[Physics:Quantum mechanics|quantum mechanics]]. [[Biography:Albert Einstein|Albert Einstein]], in 1905, published the so-called "[[Physics:Annus Mirabilis papers|Annus Mirabilis papers]]", one of which explained the [[Physics:Photoelectric effect|photoelectric effect]], based on [[Biography:Max Planck|Max Planck]]'s discovery of energy quanta which was the foundation of quantum mechanics, another of which described [[Physics:Special relativity|special relativity]], and the last of which explained [[Brownian motion]] in terms of [[Physics:Statistical mechanics|statistical mechanics]], providing a strong argument for the existence of atoms.

===Pronouncements later proven to be false===<!--do not change this to "proved" because that breaks the link in many articles and because it's old-fashioned prescriptivism and an MOS:ENGVAR issue – see also https://en.oxforddictionaries.com/definition/prove-->
Like many scientists, Thomson made some mistakes in predicting the future of technology.

His biographer Silvanus P. Thompson writes that "When [[Biography:Wilhelm Röntgen|Röntgen]]'s discovery of the X-rays was announced at the end of 1895, Lord Kelvin was entirely skeptical, and regarded the announcement as a hoax. The papers had been full of the wonders of Röntgen's rays, about which Lord Kelvin was intensely skeptical until Röntgen himself sent him a copy of his Memoir"; on 17 January 1896, having read the paper and seen the photographs, he wrote Röntgen a letter saying that "I need not tell you that when I read the paper I was very much astonished and delighted. I can say no more now than to congratulate you warmly on the great discovery you have made"<ref>>{{cite book|last=Thompson|first=Silvanus |title=The Life of William Thomson, Baron Kelvin of Largs|volume= 2|year=1910|publisher=MacMillan and Co., Limited|url=https://archive.org/details/lifeofwillthom02thomrich}}</ref> He would have his own hand X-rayed in May 1896.<ref>[http://royalsociety.org/page.asp?id=6002 The Royal Society, London]</ref> (See also N rays.)

His forecast for practical aviation (i.e., heavier-than-air [[Engineering:Aircraft|aircraft]]) was negative. In 1896 he refused an invitation to join the Aeronautical Society, writing that "I have not the smallest molecule of faith in aerial navigation other than ballooning or of expectation of good results from any of the trials we hear of."<ref>[http://zapatopi.net/kelvin/papers/letters.html#baden-powell Letter from Lord Kelvin to Baden Powell] 8 December 1896</ref> And in a 1902 newspaper interview he predicted that "No balloon and no aeroplane will ever be practically successful."<ref>[http://zapatopi.net/kelvin/papers/interview_aeronautics_and_wireless.html Interview] in the ''Newark Advocate'' 26 April 1902</ref>

A statement falsely attributed to Kelvin is: "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement." This has been widely misattributed to Kelvin since the 1980s, either without citation or stating that it was made in an address to the British Association for the Advancement of Science (1900).<ref>Davies, Paul and Brown, Julian. (1988) ''Superstring: A theory of everything?''. Cambridge University Press. p. 4. {{ISBN|9780521437752}}</ref> There is no evidence that Kelvin said this,<ref>Isaacson, Walter (2007)  ''Einstein: His Life and Universe''. Simon & Schuster. p. 575. {{ISBN|9781416586913}}</ref><ref name="horgan">Horgan, John (1996)  ''The End of Science''. Broadway Books. p. 19. {{ISBN|9780553061741}}</ref> and the quote is instead a paraphrase of [[Biography:Albert A. Michelson|Albert A. Michelson]], who in 1894 stated: "… it seems probable that most of the grand underlying principles have been firmly established … An eminent physicist remarked that the future truths of physical science are to be looked for in the sixth place of decimals."<ref name="horgan" /> Similar statements were given earlier by others, such as [[Biography:Philipp von Jolly|Philipp von Jolly]].<ref>{{cite book|last=Lightman|first=Alan P.|title=The discoveries: great breakthroughs in twentieth-century science, including the original papers|publisher=Alfred A. Knopf Canada|location=Toronto|year=2005|isbn=978-0-676-97789-9|page=8}}</ref> The attribution to Kelvin in 1900 is presumably a confusion with his "Two clouds" speech, delivered to the Royal Institution in 1900 (see above), and which on the contrary pointed out areas that would subsequently see revolutions.

In 1898, Kelvin predicted that only 400 years of oxygen supply remained on the planet, due to the rate of burning combustibles.<ref>{{cite news|url=https://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=EP18980730.2.105 |title=Papers Past—Evening Post—30 July 1898—A Startling Scientific Prediction |publisher=Paperspast.natlib.govt.nz |access-date=2013-09-04}}</ref><ref>{{cite web | url=http://news.google.com/newspapers?nid=1982&dat=19010716&id=yCYiAAAAIBAJ&pg=5236,534844 | archive-url=https://archive.today/20120712214331/http://news.google.com/newspapers?nid=1982&dat=19010716&id=yCYiAAAAIBAJ&sjid=AaQFAAAAIBAJ&pg=5236,534844 | url-status=dead | archive-date=2012-07-12 |title = The Evening News – Google News Archive Search}}</ref> In his calculation, Kelvin assumed that [[Earth:Photosynthesis|photosynthesis]] was the only source of free oxygen; he did not know all of the components of the [[Earth:Oxygen cycle|oxygen cycle]].{{dubious|reason=But isn't it overwhelmingly photosynthesis? See talk page.|date=March 2015}} He could not even have known all of the sources of photosynthesis: for example the cyanobacterium ''[[Biology:Prochlorococcus|Prochlorococcus]]''—which accounts for more than half of marine photosynthesis—was not discovered until 1986.

=== Eponyms ===
A variety of physical phenomena and concepts with which Thomson is associated are named ''Kelvin'', including:
{{div col|small=yes}}
*[[Physics:Kelvin bridge|Kelvin bridge]] (also known as Thomson bridge)
*[[Kelvin functions]]
*[[Physics:Kelvin–Helmholtz instability|Kelvin–Helmholtz instability]]
*Kelvin–Helmholtz luminosity
*[[Astronomy:Kelvin–Helmholtz mechanism|Kelvin–Helmholtz mechanism]]
*Kelvin material
*Joule–Kelvin effect
*[[Four-terminal sensing|Kelvin sensing]]
*[[Kelvin transform]] in potential theory
*[[Physics:Kelvin water dropper|Kelvin water dropper]]
*[[Physics:Kelvin wave|Kelvin wave]]
*[[Astronomy:Heat death paradox|Kelvin’s heat death paradox]]
*[[Kelvin's circulation theorem]]
*[[Physics:Kelvin–Stokes theorem|Kelvin–Stokes theorem]]
*[[Engineering:Kelvin–Varley divider|Kelvin–Varley divider]]
*The SI unit of temperature, [[Kelvin|kelvin]]
{{div col end}}

Mount Kelvin in New Zealand's Paparoa Range was named after him by the botanist William Trownson.<ref>{{LINZ|id=31266 |name=Mount Kelvin |access-date=21 August 2022}}</ref>

=== Honours ===
[[File:Lord Kelvin, Botanic park Belfast.jpg|thumb|upright|Statue of Kelvin; Belfast Botanic Gardens]]
*Fellow of the Royal Society of Edinburgh, 1847.
**Keith Medal, 1864.
**Gunning Victoria Jubilee Prize, 1887.
**President, 1873–1878, 1886–1890, 1895–1907.
*Foreign member of the Royal Swedish Academy of Sciences, 1851.
*Fellow of the Royal Society, 1851.
**Royal Medal, 1856.
**[[Physics:Copley Medal|Copley Medal]], 1883.
**President, 1890–1895.
*Hon. Member of the Royal College of Preceptors (College of Teachers), 1858.
*Hon. Member of the [[Organization:Institution of Engineers and Shipbuilders in Scotland|Institution of Engineers and Shipbuilders in Scotland]], 1859.<ref>{{cite web | title=Honorary Members and Fellows | publisher=Institution of Engineers in Scotland  | url=http://www.iesis.org/honorary-fellows.html | access-date=6 October 2012 }}</ref>
*Knighted 1866.<ref>{{London Gazette |issue=23185 |date=16 November 1866 |page=6062}}</ref>
*Commander of the Imperial Order of the Rose (Brazil), 1873.
*Commander of the Legion of Honour (France), 1881.
**Grand Officer of the Legion of Honour, 1889.
*Knight of the Prussian Order Pour le Mérite, 1884.
*Commander of the Order of Leopold (Belgium), 1890.
*'''Baron Kelvin''', of Largs in the County of Ayr, 1892.<ref>{{London Gazette |issue=26260 |date=23 February 1892 |page=991 }}</ref> The title derives from the River Kelvin, which runs by the grounds of the [[Organization:University of Glasgow|University of Glasgow]]. His title died with him, as he was survived by neither heirs nor close relations.[[File:The memorial of William Thomson, 1st Baron Kelvin, University of Glasgow.jpg|right|thumb|The memorial of William Thomson, Baron Kelvin in Kelvingrove Park next to the University of Glasgow]]
*Knight Grand Cross of the Victorian Order, 1896.<ref>{{London Gazette |issue=26758 |date=14 July 1896 |page=4026}}</ref>
* Honorary degree ''Legum doctor'' (LL.D.), [[Organization:Yale University|Yale University]], 5 May 1902.<ref>{{Cite newspaper The Times |title=Court Circular |date=6 May 1902 |page=5 |issue=36760}}</ref>
*One of the first members of the Order of Merit, 1902.<ref>{{London Gazette |issue=27470 |date=2 September 1902 |page=5679}}</ref>
*Privy Counsellor, 11 August 1902.<ref name=LG27464 />
*Honorary degree ''Doctor mathematicae'' from the Royal Frederick University on 6 September 1902, when they celebrated the centennial of the birth of [[Biography:Mathematician|mathematician]] [[Biography:Niels Henrik Abel|Niels Henrik Abel]].<ref>{{Cite newspaper The Times |title=Foreign degrees for British men of Science |date=8 September 1902 |page=4 |issue=36867}}</ref><ref>{{cite web|url=http://www.uio.no/om/tall-og-fakta/aresdoktorer/tidligere-aresdoktorer/1902-1910/ |title=Honorary doctorates from the University of Oslo 1902–1910}} ''(in Norwegian)''</ref>
*First international recipient of John Fritz Medal, 1905.
*Order of the First Class of the Sacred Treasure of Japan, 1901.
*He is buried in Westminster Abbey, London next to [[Biography:Isaac Newton|Isaac Newton]].
*Lord Kelvin was commemorated on the £20 note issued by the Clydesdale Bank in 1971; in the current issue of banknotes, his image appears on the bank's £100 note. He is shown holding his adjustable compass and in the background is a map of the transatlantic cable.<ref name="scotbanks">{{cite web|url=http://www.scotbanks.org.uk/banknotes_current_clydesdale_bank.php|title=Current Banknotes : Clydesdale Bank|publisher=The Committee of Scottish Clearing Bankers|access-date=15 October 2008}}</ref>
*In 2011 he was one of seven inaugural inductees to the Scottish Engineering Hall of Fame.<ref>{{cite web |url= http://www.engineeringhalloffame.org/index.html |title=Scottish Engineering Hall of Fame |website=engineeringhalloffame.org |year=2012 |access-date=27 August 2012}}</ref>
*[[Physics:World Refrigeration Day|World Refrigeration Day]], is 26 June. It was chosen to celebrate his birth date and has been held annually, since 2019.

=== Arms ===
{{Infobox COA wide
| image             = William Thomson Arms.svg
| bannerimage       =
| badgeimage        =
| notes             = The arms of Lord Kelvin consist of:<ref>{{cite book|last=Thompson|first=Silvanus |title=The Life of William Thomson, Baron Kelvin of Largs|volume= 2|year=1910|publisher=MacMillan and Co., Limited |page=914|url=https://archive.org/details/lifeofwillthom02thomrich}}</ref>
| adopted           =
| crest             = A cubit arm erect, vested azure, cuffed argent, the hand grasping five ears of rye proper.
| torse             =
| helm              =
| escutcheon        = Argent, a stag's head caboshed gules, on a chief azure a thunderbolt proper, winged or, between two spur revels of the first.
| supporters        = On the dexter side a student of the University of Glasgow, habited, holding in his dexter hand a marine voltmeter, all proper. On the sinister side a sailor, habited, holding in the dexter hand a coil, the rope passing through the sinister, and suspended therefrom a sinker of a sounding machine, also all proper.
| compartment       =
| motto             = Honesty without fear.
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== See also ==
*[[Physics:Taylor column|Taylor column]]
*People on Scottish banknotes
*List of things named after Lord Kelvin
**[[Kelvin]] (unit)

== References ==
{{reflist|colwidth=30em}}

== Cited sources ==
*{{cite book |ref = Lindley| author=Lindley, D. | title=Degrees Kelvin: A Tale of Genius, Invention and Tragedy | year=2004 | publisher=Joseph Henry Press | isbn=978-0-309-09073-5 | url=https://archive.org/details/degreeskelvintal0000lind }}
*{{cite book | ref = Sharlin| author=Sharlin, H.I. | title=Lord Kelvin: The Dynamic Victorian | publisher=Pennsylvania State University Press | year=1979 | isbn=978-0-271-00203-3 }}

=== Kelvin's works ===
{{refbegin}}
*{{cite book | last1=Thomson | first1=W. | last2=Tait |first2=P.G. | title=Treatise on Natural Philosophy | publisher=Oxford | year=1867 }} 2nd edition, 1883. (reissued by {{wipe|Cambridge University Press}}, 2009. {{ISBN|978-1-108-00537-1}})
**''[https://archive.org/details/treatisnatphil01kelvrich Treatise on Natural Philosophy (Part I)]'' ([[Internet Archive]])
**''[https://archive.org/details/treatisnatphil02kelvrich Treatise on Natural Philosophy (Part II)]'' ([[Internet Archive]])
*{{cite book | last1=Thomson | first1=W. | author-mask=2 | last2=Tait | first2=P.G | title=Elements of Natural Philosophy | year=1872 | url=https://archive.org/details/elementsnatural00kelvgoog | publisher=At the University press }} (reissued by {{wipe|Cambridge University Press}}, 2010. {{ISBN|978-1-108-01448-9}}) 2nd edition, 1879.
* {{Cite book|title=Elasticity and heat|publisher=Adam & Charles Black|location=Edinburgh|year=1880|url=https://gutenberg.beic.it/webclient/DeliveryManager?pid=6480219}}
*{{cite book | last1=Thomson | first1=W. | title=Shakespeare and Bacon on Vivisection | publisher=Sands & McDougall | year=1881 | url=https://books.google.com/books?id=-KcNAAAAQAAJ&q=Bacon+and+Shakespeare+on+Vivisection&pg=PA5 }}
*{{cite book | last1=Thomson | first1=W. | author-mask=2 | last2=Tait | first2=P.G | title=Elements of Natural Philosophy | year=1872 | url=https://archive.org/details/elementsnatural00kelvgoog | publisher=At the University press }} (reissued by {{wipe|Cambridge University Press}}, 2010. {{ISBN|978-1-108-01448-9}}) 2nd edition, 1879.
*{{cite book | last=Thomson | first=W. | author-mask=2 | title=Mathematical and Physical Papers | publisher=Cambridge University Press | year=1882–1911 | url=http://catalog.hathitrust.org/Record/000167345 }} (6 volumes)
** [https://archive.org/details/mathematicaland01kelvgoog Volume I. 1841–1853] ([[Internet Archive]])
** [https://archive.org/details/mathematicaland02kelvgoog Volume II. 1853–1856] ([[Internet Archive]])
** [https://archive.org/details/mathematicaland03kelvgoog Volume III. Elasticity, heat, electro-magnetism] ([[Internet Archive]])
** [http://babel.hathitrust.org/cgi/pt?id=miun.aat1571.0004.001;view=1up;seq=3 Volume IV. Hydrodynamics and general dynamics] (Hathitrust)
** [https://archive.org/details/mathematicalphys05kelvuoft Volume V. Thermodynamics, cosmical and geological physics, molecular and crystalline theory, electrodynamics] ([[Internet Archive]])
** [https://archive.org/details/mathematicalphys06kelvuoft Volume VI. Voltaic theory, radioactivity, electrions, navigation and tides, miscellaneous] ([[Internet Archive]])
*{{Cite journal | last=Thomson | first=W. | author-mask=2 | title=Baltimore Lectures on Molecular Dynamics and the Wave Theory of Light | journal=Baltimore Lectures on Molecular Dynamics and the Wave Theory of Light | year=1904 | url=https://archive.org/details/baltimorelecture00kelviala | bibcode=2010blmd.book.....T }} (reissued by {{wipe|Cambridge University Press}}, 2010. {{ISBN|978-1-108-00767-2}})
*{{Cite journal | last=Thomson | first=W. | author-mask=2 | title=Collected Papers in Physics and Engineering | journal=Nature | volume=90 | issue=2256 | pages=563–565 | year=1912 | asin=B0000EFOL8 | bibcode=1913Natur..90..563P | doi=10.1038/090563a0 | s2cid=3957852 }}
*{{cite book | editor-last=Wilson | editor-first=D.B.  | title=The Correspondence Between Sir George Gabriel Stokes and Sir William Thomson, Baron Kelvin of Largs | publisher=(2 vols), Cambridge University Press | year=1990 | isbn=978-0-521-32831-9 }}
*{{cite book | last=Hörz | first=H. | title=Naturphilosophie als Heuristik?: Korrespondenz zwischen Hermann von Helmholtz und Lord Kelvin (William Thomson) | publisher=Basilisken-Presse | year=2000 | isbn=978-3-925347-56-6 }}
{{refend}}

=== Biography, history of ideas and criticism ===
{{refbegin|2}}
*{{cite journal | author=Buchwald, J.Z. | year=1977 | title=William Thomson and the mathematization of Faraday's electrostatics | journal=Historical Studies in the Physical Sciences | volume=8 | pages=101–136 | doi=10.2307/27757369| jstor=27757369 }}
*{{cite journal | author=Cardoso Dias, D.M. | year=1996 | title=William Thomson and the Heritage of Caloric | journal=Annals of Science | volume=53 | pages=511–520 | doi=10.1080/00033799600200361 | issue=5 }}
*{{cite journal | author=Gooding, D. | year=1980 | title=Faraday, Thomson, and the concept of the magnetic field | journal=British Journal for the History of Science | volume=13 | pages=91–120 | doi=10.1017/S0007087400017726 | issue=2 | s2cid=145573114 }}
*{{cite journal | author=Gossick, B.R. | year=1976 | title=Heaviside and Kelvin: a study in contrasts | journal=Annals of Science | volume=33 | pages=275–287  | doi = 10.1080/00033797600200561 | issue=3}}
*{{cite book | author=Gray, A. | title=Lord Kelvin: An Account of His Scientific Life and Work | url=https://archive.org/details/in.ernet.dli.2015.53570 | year=1908 | location=London | publisher=J. M. Dent & Co }}
*{{Cite journal |author1=Green, G.  |author2=Lloyd, J.T.  |name-list-style=amp | title=Kelvin's instruments and the Kelvin Museum |journal=American Journal of Physics  |volume=40  |issue=3  |page=496  | year=1970 | isbn=978-0-85261-016-9 |bibcode=1972AmJPh..40..496G  |doi=10.1119/1.1986598  }}
*{{cite book | author=Hearn, Chester G. | title=Circuits in the Sea: the men, the ships, and the Atlantic cable | year=2004 | location=Westport, Connecticut | publisher=Praeger }}
*{{Cite journal | editor1=Kargon, R.H. |editor2= Achinstein, P.| year=1987 | title=Kelvin's Baltimore Lectures and Modern Theoretical Physics; Historical and Philosophical Perspectives | journal=Physics Today | volume=42 | issue=1 | pages=82–84 | isbn=978-0-262-11117-1 | bibcode=1989PhT....42a..82K | doi=10.1063/1.2810888 | url=https://archive.org/details/kelvinsbaltimore00lord/page/82 |last1= Kargon|first1= Robert|last2= Achinstein|first2= Peter|last3= Brown|first3= Laurie M.}}
*{{Cite journal | author=King, A.G. | year=1925 | title=Kelvin the Man | journal=Nature | volume=117 | issue=2933 | page=79 | bibcode=1926Natur.117R..79. | doi=10.1038/117079b0 | s2cid=4094894 }}
*{{Cite journal | author=King, E.T. | year=1909 | title=Lord Kelvin's Early Home | journal=Nature | volume=82 | issue=2099 | pages=331–333 | bibcode=1910Natur..82..331J | doi=10.1038/082331a0 | s2cid=3974629 | url=https://zenodo.org/record/2442316 }}
*{{cite journal | author=Knudsen, O. | year=1972 | title=From Lord Kelvin's notebook: aether speculations | journal=Centaurus | volume=16 | issue=1 | pages=41–53  | doi = 10.1111/j.1600-0498.1972.tb00164.x|bibcode = 1972Cent...16...41K }}
*{{cite journal | author=Lekner, J. | title=Nurturing genius: the childhood and youth of Kelvin and Maxwell| year=2012 | journal=New Zealand Science Review|url=http://www.victoria.ac.nz/scps/about/staff/pdf/Nurturing-genius.pdf }}
*{{cite book | editor1=McCartney, M. |editor2= Whitaker, A. | title=Physicists of Ireland: Passion and Precision | year=2002 | publisher=Institute of Physics Publishing | isbn=978-0-7503-0866-3 }}
*{{cite journal | year=1979 | author=May, W.E. | title=Lord Kelvin and his compass | journal=Journal of Navigation | volume=32 | pages=122–134 | doi=10.1017/S037346330003318X | s2cid=122538244 }}
*{{cite book | author=Munro, J. | year=1891 | title=Heroes of the Telegraph | url=https://archive.org/details/cu31924031222494 | publisher=London: Religious Tract Society }}
*{{cite book | author=Murray, D. | year=1924 | title=Lord Kelvin as Professor in the Old College of Glasgow | publisher=Glasgow: Maclehose & Jackson }}
*{{cite book | author=Russell, A. | year=1912 | title=Lord Kelvin: His Life and Work | publisher=London: T.C. & E.C.Jack| url=https://archive.org/stream/lordkelvinhislif00russ#page/n5/mode/2up |access-date=25 March 2014 }}
*{{cite book |author1=Smith, C.  |author2=Wise, M.N.  |name-list-style=amp | title=Energy and Empire: A Biographical Study of Lord Kelvin | publisher=Cambridge University Press | year=1989 | isbn=978-0-521-26173-9 | url=https://books.google.com/books?id=2JYWeyAXpHUC&pg=PR7 |access-date=25 March 2014 }}
*{{cite book | author=Thompson, S.P. | title=Life of William Thomson: Baron Kelvin of Largs | url=https://archive.org/details/b31360403_0001 | publisher=Macmillan | location=London | year=1910 }} In two volumes [https://archive.org/stream/lifeofwilliamtho01thomuoft#page/n9/mode/2up Volume 1] [https://archive.org/stream/lifeofwillthom02thomrich#page/n7/mode/2up Volume 2]
*{{cite book | author=Tunbridge, P. | title=Lord Kelvin: His Influence on Electrical Measurements and Units | location=Peter Peregrinus | publisher=London | year=1992 | isbn=978-0-86341-237-0}}
*{{cite book | author=Wilson, D. | year=1910 | title=William Thomson, Lord Kelvin: His Way of Teaching | publisher=Glasgow: John Smith & Son }}
*{{cite book | author=Wilson, D.B. | title=Kelvin and Stokes: A Comparative Study in Victorian Physics | year=1987 | location=Bristol | publisher=Hilger | isbn=978-0-85274-526-7 }}
{{refend}}

== External links ==
{{EB1911 poster|Kelvin, William Thomson, Baron}}
* {{Gutenberg author|id=48139}}
* {{MacTutor Biography|id=Thomson}}
* {{Internet Archive author |sname=William Thomson, 1st Baron Kelvin}}
* {{Librivox author |id=10522}}
* [http://onlinebooks.library.upenn.edu/webbin/gutbook/lookup?num=979 ''Heroes of the Telegraph''] at The Online Books Page
* [https://web.archive.org/web/20071203034027/https://sheemere.hautetfort.com/archive/2007/10/16/des-chevaux-sur-mars.html "Horses on Mars", from Lord Kelvin]
* [http://physicsweb.org/articles/world/15/12/6 William Thomson: king of Victorian physics] at [[Organization:Institute of Physics|Institute of Physics]] website
* ''[http://www.lse.ac.uk/CPNSS/pdf/DP_withCover_Measurement/Meas-DP%2026%2002%20C.pdf Measuring the Absolute: William Thomson and Temperature] {{Webarchive|url=https://web.archive.org/web/20190502045339/http://www.lse.ac.uk/CPNSS/pdf/DP_withCover_Measurement/Meas-DP%2026%2002%20C.pdf |date=2 May 2019 }}'', [[Biography:Hasok Chang|Hasok Chang]] and Sang Wook Yi ([[PDF]] file)
* ''[http://gallica.bnf.fr/notice?N=FRBNF37278042 Reprint of papers on electrostatics and magnetism]'' (gallica)
* ''[https://archive.org/details/moleculartactics00kelviala The molecular tactics of a crystal]'' ([[Internet Archive]])
* ''[http://zapatopi.net/kelvin/quotes/ Quotations. This collection includes sources for many quotes.]''
* [https://web.archive.org/web/20100412061437/http://science.theleys.net/kelvin.htm Kelvin Building Opening – The Leys School, Cambridge (1893)]
* [http://zapatopi.net/kelvin/papers/ The Kelvin Library]

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{{s-bef|before=[[Biography:Sir George Stokes, 1st Baronet|George Stokes]]}}
{{s-ttl|order=36th|title=President of the Royal Society|years=1890–1895}}
{{s-aft|after=Joseph Lister}}
{{s-break}}
{{s-aca}}
{{s-bef|before = The Earl of Stair}}
{{s-ttl|title  = Chancellor of the University of Glasgow|years  = 1904–1907}}
{{s-aft|after  = The Earl of Rosebery}}
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{{s-end}}

{{Royal Society presidents 1800s}}
{{Scientists whose names are used as SI units}}

{{DEFAULTSORT:Kelvin, William Thomson, 1st Baron}}
[[Category:Fluid dynamicists]]

{{Sourceattribution|William Thomson, 1st Baron Kelvin|1}}