View source for Joseph Larmor

{{Short description|Irish mathematician and physicist (1857–1942)}}
{{redirect|Larmor}}
{{EngvarB|date=October 2013}}
{{Use dmy dates|date=December 2024}}
{{Infobox scientist
| honorific_prefix  = [[Sir]]
| honorific_suffix  = {{postnominals|size=100%|FRS|FRSE}}
| image             = Joseph Larmor.jpeg
| caption           = Larmor, {{circa|1920}}
| birth_date        = {{birth date|df=y|1857|7|11}}
| birth_place       = Magheragall, [[County Antrim]], Ireland
| death_date        = {{death date and age|df=y|1942|5|19|1857|7|11}}
| death_place       = [[Holywood, County Down]], Northern Ireland<ref>{{MacTutor Biography|id=Larmor}}</ref>
| alma_mater        = {{tree list}}
*[[Queen's University Belfast]] ([[Bachelor of Arts|BA]], 1874; [[Master of Arts|MA]], 1875)
*[[University of Cambridge]]
**[[St John's College, Cambridge|St John's College]] (MA, 1883)
{{tree list/end}}
| known_for         = {{plainlist|
* Formulating the [[Larmor formula]] (1897)
* Postulating [[time dilation]] (1897)
}}
| awards            = {{plainlist|
*[[Smith's Prize]] (1880)
*[[Fellow of the Royal Society|FRS]] (1892)
*[[Adams Prize]] (1899)
*[[De Morgan Medal]] (1914)
*[[Royal Medal]] (1915)
*[[Poncelet Prize]] (1918)
*[[Copley Medal]] (1921)
}}
| fields            = {{tree list}}
*[[Mathematics]]
*[[Physics]]
**[[Electromagnetism]]
**[[Relativistic mechanics]]
{{tree list/end}}
| work_institutions = {{plainlist|
*[[Queen's College Galway]] (1883–1885)
* University of Cambridge (1885–1932)
}}
| academic_advisors = {{plainlist|
*[[John Purser (mathematician)|John Purser]]
*[[Edward Routh]]
}}
| doctoral_students = [[Kwan-ichi Terazawa]]
{{Infobox officeholder
| embed             = yes
| office            = Lucasian Professor of Mathematics 
| order             = 14th
| term_start        = 1903
| term_end          = 1932
| predecessor       = [[Sir George Stokes, 1st Baronet|George Stokes]]
| successor         = [[Paul Dirac]]
}}
}}

'''Sir Joseph Larmor''' ({{IPAc-en|ˈ|l|ɑːr|m|ɒr}}; 11 July 1857 – 19 May 1942) was an Irish<ref>{{Cite web|url=https://www.britannica.com/biography/Joseph-Larmor|title=Sir Joseph Larmor &#124; Irish physicist &#124; Britannica}}</ref> [[mathematician]] and [[physicist]] who made breakthroughs in the understanding of [[electricity]], [[dynamics (mechanics)|dynamics]], [[thermodynamics]], and the [[electron]] theory of [[matter]]. His most influential work was ''Aether and Matter'', a [[theoretical physics]] book published in 1900.

==Biography==
He was born in [[Magheragall]] in [[County Antrim]], the son of Hugh Larmor, a [[Belfast]] shopkeeper and his wife, Anna Wright.<ref>{{cite book|title=Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002|date=July 2006|publisher=[[The Royal Society of Edinburgh]]|isbn=0-902-198-84-X|url=https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|access-date=12 March 2017|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304074135/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|url-status=dead}}</ref> The family moved to Belfast circa 1860, and he was educated at the [[Royal Belfast Academical Institution]], and then studied mathematics and experimental science at [[Queen's College, Belfast]] (BA 1874, MA 1875),<ref>[http://lisburn.com/history/digger/Digger-2011/digger-06-05-2011.html From Ballycarrickmaddy to the moon] Lisburn.com, 6 May 2011</ref> where one of his teachers was [[John Purser (mathematician)|John Purser]]. He subsequently studied at [[St John's College, Cambridge]], where in 1880 he was [[Senior Wrangler]] ([[J. J. Thomson]] was second wrangler that year) and Smith's Prizeman, getting his MA in 1883.<ref>{{acad|id=LRMR876J|name=Larmor, Joseph}}</ref> After teaching physics for a few years at [[Queen's College, Galway]], he accepted a lectureship in mathematics at Cambridge in 1885. In 1892 he was elected a fellow of the [[Royal Society of London]], and he served as one of the Secretaries of the society.<ref>{{Cite newspaper The Times |title= Court Circular|date=7 November 1902 |page=8 |issue=36919}}</ref> He was made an honorary fellow of the [[Royal Society of Edinburgh]] in 1910.<ref>{{cite book|title=Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002|date=July 2006|publisher=The Royal Society of Edinburgh|isbn=0-902-198-84-X|url=https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|access-date=12 March 2017|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304074135/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|url-status=dead}}</ref>

In 1903 he was appointed [[Lucasian Professor of Mathematics]] at Cambridge, a post he retained until his retirement in 1932. He never married.<ref>{{Cite web |title=Joseph Larmor – Biography |url=https://mathshistory.st-andrews.ac.uk/Biographies/Larmor/ |access-date=2024-04-05 |website=Maths History |language=en}}</ref> He was knighted by King [[Edward VII]] in 1909.

Motivated by his strong opposition to [[Devolution|Home Rule for Ireland]], in February 1911 Larmor ran for and was elected as Member of Parliament for [[Cambridge University (UK Parliament constituency)]] with the [[Conservative Party (UK)|Conservative party]]. He remained in parliament until the [[1922 United Kingdom general election|1922 general election]], at which point the Irish question had been settled. Upon his retirement from Cambridge in 1932, Larmor moved back to [[County Down]] in Northern Ireland.

He received an honorary [[Legum Doctor|Doctor of Laws]] (LLD) from the [[University of Glasgow]] in June 1901.<ref name="frs">{{Cite journal | last1 = Eddington | first1 = A. S. | author-link = Arthur Eddington| title = Joseph Larmor. 1857–1942 | doi = 10.1098/rsbm.1942.0016 | journal = [[Obituary Notices of Fellows of the Royal Society]] | volume = 4 | issue = 11 | pages = 197–207 | year = 1942 | doi-access = free }}</ref><ref>{{Cite news |url=https://www.newspapers.com/article/the-times-glasgow-university-jubilee/131294008/ |date=14 June 1901 |title=Glasgow University Jubilee |page=10 |newspaper=[[The Times]] |publication-place=London |issue=36481 |access-date=2024-01-05 |via=Newspapers.com}}</ref> He received an honorary Doctor in Science from [[Trinity College Dublin]] in 1903.<ref>{{cite book |date=1907 |title=Dublin University Calendar, A Special Supplemental Volume for the year 1906-7 |location=Dublin |publisher=Hodges, Figgis, and Co. Ltd. |volume=III}}</ref> He was elected an International Honorary Member of the [[American Academy of Arts and Sciences]] in 1903, an International Member of the United States [[National Academy of Sciences]] in 1908, and an International Member of the [[American Philosophical Society]] in 1913.<ref>{{Cite web |date=2023-02-09 |title=Joseph Larmor |url=https://www.amacad.org/person/joseph-larmor |access-date=2023-11-15 |website=American Academy of Arts & Sciences |language=en}}</ref><ref>{{Cite web |title=Joseph Larmor |url=https://www.nasonline.org/member-directory/deceased-members/20001333.html |access-date=2023-11-15 |publisher=National Academy of Sciences}}</ref><ref>{{Cite web |title=APS Member History |url=https://search.amphilsoc.org/memhist/search?creator=Joseph+Larmor&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced |access-date=2023-11-15 |website=search.amphilsoc.org}}</ref> He was awarded the [[Poncelet Prize]] for 1918 by the [[French Academy of Sciences]].<ref>{{cite journal|title=Prize Awards of the Paris Academy of Sciences for 1918|journal=Nature|volume=102|issue=2565|pages=334–335|date=26 December 1918|doi=10.1038/102334b0|bibcode = 1918Natur.102R.334. |doi-access=free}}</ref> Larmor was a Plenary Speaker in 1920 at the [[International Congress of Mathematicians|ICM]] at Strasbourg<ref>{{cite book|chapter-url=http://www.mathunion.org/ICM/ICM1920/Main/icm1920.0003.0040.ocr.pdf|pages=3–40|year=1921|title=Compte rendu du Congrès international des mathématiciens tenu à Strasbourg du 22 au 30 Septembre 1920|chapter=''Questions in physical indetermination'' by Joseph Larmor|url-status=dead|archive-url=https://web.archive.org/web/20131227061941/http://www.mathunion.org/ICM/ICM1920/Main/icm1920.0003.0040.ocr.pdf|archive-date=27 December 2013}}</ref><ref>{{cite journal|title=The International Congress of Mathematicians|journal=Nature|date=7 October 1920|volume=106|issue=2658|pages=196–197|url=https://books.google.com/books?id=YBJLAQAAMAAJ&pg=PA196|bibcode=1920Natur.106..196H|doi=10.1038/106196a0|last1=H|first1=H. B.|doi-access=free}} In his plenary address, Larmor advocated the aether theory as opposed to Einstein's general theory of relativity.</ref> and an Invited Speaker at the ICM in 1924 in Toronto and at the ICM in 1928 in Bologna.

He died in [[Holywood, County Down]] on 19 May 1942.<ref>{{cite book|title=Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002|date=July 2006|publisher=The Royal Society of Edinburgh|isbn=0-902-198-84-X|url=https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|access-date=12 March 2017|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304074135/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|url-status=dead}}</ref>

==Work==
Larmor proposed that the [[Luminiferous aether|aether]] could be represented as a [[Homogeneous (chemistry)|homogeneous]] [[fluid]] medium which was perfectly [[incompressible]] and [[Elasticity (physics)|elastic]]. Larmor believed the aether was separate from matter. He united [[William Thomson, 1st Baron Kelvin|Lord Kelvin]]'s model of spinning [[gyrostat]]s (see [[Vortex theory of the atom]]) with this [[theory]]. Larmor held that [[matter]] consisted of [[Elementary particle|particles]] moving in the aether. Larmor believed the source of [[electric charge]] was a "''particle''" (which as early as 1894 he was referring to as the [[electron]]). Larmor held that the flow of charged particles constitutes the [[Current (electricity)|current]] of [[conductor (material)|conduction]] (but was not part of the [[atom]]). Larmor calculated the rate of energy [[radiation]] from an [[acceleration|accelerating]] electron. Larmor explained the splitting of the [[spectral line]]s in a [[magnetic field]] by the [[oscillation]] of electrons.<ref>Histories of the Electron: The Birth of Microphysics
edited by Jed Z. Buchwald, Andrew Warwick</ref>[[File:Delegates to the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory.jpg|thumb|Larmor at the Fourth Conference International Union for Cooperation in Solar Research at [[Mount Wilson Observatory]], 1910]]Larmor also created the first solar system model of the atom in 1897.<ref>The Zeeman Effect and the Discovery of the Electron, Theodore Arabatzis, 2001.</ref> He also postulated the proton, calling it a "positive electron". He said the destruction of this type of atom making up matter "is an occurrence of infinitely small probability".

In 1919, Larmor proposed [[sunspot]]s are [[Regenerative circuit|self-regenerative]] [[dynamo]] action on the [[Sun]]'s surface.

Quotes from one of Larmor's voluminous work include:
* "while atoms of matter are in whole or in part aggregations of electrons in stable orbital motion. In particular, this scheme provides a consistent foundation for the electrodynamic laws, and agrees with the actual relations between radiation and moving matter".
* "A formula for optical dispersion was obtained in § 11 of the second part of this memoir, on the simple hypothesis that the electric polarization of the molecules vibrated as a whole in unison with the electric field of the radiation".
* “…that of the transmission of radiation across a medium permeated by molecules, each consisting of a system of electrons in steady orbital motion, and each capable of free oscillations about the steady state of motion with definite free periods analogous to those of the planetary inequalities of the Solar System;”
* “'A' will be a positive electron in the medium, and 'B' will be the complementary negative one...We shall thus have created two permanent conjugate electrons A and B; each of them can be moved about through the medium, but they will both persist until they are destroyed by an extraneous process the reverse of that by which they are formed".<ref>”A Dynamical Theory of the Electric and Luminiferous Medium.— Part III". Joseph Larmor, Phil. Trans., A, vol. 190, 1897, pp. 205–300.</ref>

==Discovery of Lorentz transformation==
{{Main|History of Lorentz transformations#Larmor|History of special relativity}}
[[File:Larmor-1.jpg|alt=1900 copy of "Aether and Matter"|left|thumb|220x220px|1900 copy of "Aether and Matter"]]
Parallel to the development of [[Lorentz ether theory]], Larmor published an approximation to the [[Lorentz transformation]]s in the ''[[Philosophical Transactions of the Royal Society]]'' in 1897,<ref>{{Citation |author=Larmor, Joseph |year=1897 |title=On a Dynamical Theory of the Electric and Luminiferous Medium, Part 3, Relations with material media |journal=Philosophical Transactions of the Royal Society |volume=190 |pages=205–300 |doi=10.1098/rsta.1897.0020|bibcode = 1897RSPTA.190..205L |title-link=s:Dynamical Theory of the Electric and Luminiferous Medium III |doi-access=free }}</ref>
namely <math>x_{1}  =x\epsilon^{\frac{1}{2}}</math> for the spatial part and <math>dt_{1}  =dt^{\prime}\epsilon^{-\frac{1}{2}}</math> for the temporal part, where <math>\epsilon =\left(1-v^{2}/c^{2}\right)^{-1}</math> and the local time <math>t^{\prime} =t-vx/c^{2}</math>. He obtained the full Lorentz transformation in 1900 by inserting <math>\epsilon</math> into his expression of local time such that <math>t^{\prime\prime} =t^{\prime}-\epsilon vx^{\prime}/c^{2}</math>, and as before <math>x_{1} =\epsilon^{\frac{1}{2}}x^{\prime}</math> and <math>dt_{1} =\epsilon^{-\frac{1}{2}}dt^{\prime\prime}</math>.<ref>{{Citation |author=Larmor, Joseph |year=1900 |title=Aether and Matter |publisher=Cambridge University Press|title-link=s:Aether and Matter }}</ref> This was done around the same time as [[Hendrik Lorentz]] (1899, 1904) and five years before [[Albert Einstein]] (1905).

Larmor however did not possess the correct velocity transformations, which include the addition of velocities law, which were later discovered by [[Henri Poincaré]]. Larmor predicted the [[phenomenon]] of [[time dilation]], at least for orbiting electrons, by writing (Larmor 1897): "... individual electrons describe corresponding parts of their orbits in times shorter for the [rest] system in the ratio&nbsp;(1&nbsp;–&nbsp;''v''<sup>2</sup>/''c''<sup>2</sup>)<sup>1/2</sup>". He also verified that the [[FitzGerald–Lorentz contraction]] ([[length contraction]]) should occur for bodies whose atoms were held together by electromagnetic forces. In his book ''Aether and Matter'' (1900), he again presented the Lorentz transformations, time dilation and length contraction (treating these as dynamic rather than [[kinematic]] effects). Larmor was opposed to the [[spacetime]] interpretation of the Lorentz transformation in [[special relativity]] because he continued to believe in an absolute aether. He was also critical of the [[space-time|curvature of space]] of [[general relativity]], to the extent that he claimed that an absolute time was essential to astronomy (Larmor 1924, 1927).

==Publications==
* 1884, "Least action as the fundamental formulation in dynamics and physics", ''Proceedings of the London Mathematical Society''.
* 1887, "On the direct applications of first principles in the theory of partial differential equations", ''[[Proceedings of the Royal Society]]''.
* 1891, "On the theory of electrodynamics", ''Proceedings of the Royal Society''.
* 1892, "On the theory of electrodynamics, as affected by the nature of the mechanical stresses in excited dielectrics", ''Proceedings of the Royal Society''.
* 1893–97, "Dynamical Theory of the Electric and Luminiferous Medium", ''Proceedings of the Royal Society; Philosophical Transactions of the Royal Society''. Series of 3 papers containing Larmor's physical theory of the universe.
* 1896, "The influence of a magnetic field on radiation frequency", ''Proceedings of the Royal Society''.
* 1896, "On the absolute minimum of optical deviation by a prism", ''Proceedings of the Cambridge Philosophical Society''.
*{{Cite journal | last1 = Larmor | first1 = J. | doi = 10.1098/rsta.1897.0020 | title = A Dynamical Theory of the Electric and Luminiferous Medium. Part III. Relations with Material Media | journal = Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | volume = 190 | pages = 205–493 | year = 1897 |bibcode = 1897RSPTA.190..205L | doi-access = free }}
* 1898, "Note on the complete scheme of electrodynamic equations of a moving material medium, and electrostriction", ''Proceedings of the Royal Society''.
* 1898, "On the origin of magneto-optic rotation", ''Proceedings of the Cambridge Philosophical Society''.
* {{Citation | author=Larmor, J. | year=1900 | title=Aether and Matter | publisher=Cambridge University Press| title-link=s:Aether and Matter }}; Containing the [[Lorentz transformation]]s on p.&nbsp;174.
* 1903, "On the electrodynamic and thermal relations of energy of magnetisation", ''Proceedings of the Royal Society''.
* 1904, "On the mathematical expression of the principle of Huygens" (read 8 Jan. 1903), ''Proceedings of the London Mathematical Society'', Ser.{{nnbsp}}2, vol.{{nnbsp}}1 (1904), pp.{{nnbsp}}1–13.
* 1907, "Aether" in ''[[Encyclopædia Britannica]]'', 11th ed.  London.
* 1908, "William Thomson, Baron Kelvin of Largs. 1824–1907" (Obituary). ''Proceedings of the Royal Society''.
* 1921, "On the mathematical expression of the principle of Huygens – {{serif|II}}" (read 13 Nov. 1919), ''Proceedings of the London Mathematical Society'', Ser.{{nnbsp}}2, vol.{{nnbsp}}19 (1921), pp.{{nnbsp}}169–80.
* 1924, "On Editing Newton", ''Nature''.
* 1927, "Newtonian time essential to astronomy", ''Nature''.
* 1929, ''Mathematical and Physical Papers''. Cambridge Univ. Press.<ref>{{cite journal|author=Gronwall, T. H.|author-link=Thomas Hakon Grönwall|title=Review: ''Mathematical and Physical Papers'', by Sir Joseph Larmor|journal=Bull. Amer. Math. Soc.|year=1930|volume=36|issue=7|pages=470–471|url=https://www.ams.org/journals/bull/1930-36-07/S0002-9904-1930-04975-7/S0002-9904-1930-04975-7.pdf|doi=10.1090/s0002-9904-1930-04975-7|doi-access=free}}</ref>
* 1937, (as editor), ''Origins of Clerk Maxwell's Electric Ideas as Described in Familiar Letters to William Thomson''. Cambridge University Press.<ref>{{cite journal|author=Page, Leigh|author-link=Leigh Page|title=Review: ''Origins of Clerk Maxwell's Electric Ideas as Described in Familiar Letters to William Thomson'', by Sir Joseph Larmor|journal=Bull. Amer. Math. Soc.|year=1938|volume=44|issue=5|pages=320|url=https://www.ams.org/journals/bull/1938-44-05/S0002-9904-1938-06738-9/S0002-9904-1938-06738-9.pdf|doi=10.1090/s0002-9904-1938-06738-9|doi-access=free}}</ref>
Larmor edited the collected works of [[Sir George Stokes, 1st Baronet|George Stokes]], [[James Thomson (engineer)|James Thomson]] and [[William Thomson, 1st Baron Kelvin|William Thomson]].<gallery>
File:Larmor-2.jpg|Title page to a 1900 copy of "Aether and Matter"
File:Larmor-3.jpg|First page of the preface to "Aether and Matter"
File:Larmor-4.jpg|First page of "Aether and Matter"
</gallery>

==See also==
{{wikisource author}}
* {{wikiquote-inline}}
*[[History of Lorentz transformations]]
*[[Dynamo theory]]
*[[Larmor precession]]
*[[Larmor (crater)]]

==References==
{{reflist}}

==Further reading==
* Bruce J. Hunt (1991), ''[[The Maxwellians]]'', Cornell University Press.
* Macrossan, M. N. "[https://web.archive.org/web/20161013173619/http://photontheory.com/larmor.pdf A note on relativity before Einstein]", ''British Journal for the Philosophy of Science'', '''37''' (1986): 232–234.
* Warwick, Andrew, "''On the Role of the FitzGerald–Lorentz Contraction Hypothesis in the Development of Joseph Larmor's Electronic Theory of Matter''". Archive for History of Exact Sciences 43 (1991): 29–91.
* {{Citation|author=Darrigol, O. |title=The Electron Theories of Larmor and Lorentz: A Comparative Study |year=1994 |journal=Historical Studies in the Physical and Biological Sciences |volume=24|issue=2 |pages=265–336 |doi=10.2307/27757725|jstor=27757725 }}
* "''[https://web.archive.org/web/20061004061956/http://www.universityscience.ie/pages/scientists/sci_josephlarmor.php A very short biography of Joseph Larmor]''"
* "''[http://www.victorianweb.org/science/ether.htm Ether and field theories in the late 19th century]''" At ''VictorianWeb:'' History of science in the Victorian era
* "''[http://janus.lib.cam.ac.uk/db/node.xsp?id=EAD%2FGBR%2F0275%2FLarmor;recurse=1 Papers of Sir Joseph Larmor]''". Janus, University of Cambridge.
* {{cite TIWW |article=Larmor, Sir Joseph |page=132 }}

==External links==
*{{Commons category-inline}}

{{S-start}}
{{s-par|uk}}
{{Succession box
 | title  = Member of Parliament for [[Cambridge University (UK Parliament constituency)|Cambridge University]]
 | years  = [[1911 Cambridge University by-election|1911]] – [[1922 United Kingdom general election|1922]]
 | with   = [[John Rawlinson (footballer and MP)|John Rawlinson]]
 | before = [[Samuel Butcher (classicist)|Samuel Butcher]]<br />[[John Rawlinson (footballer and MP)|John Rawlinson]]
 | after  = [[J. R. M. Butler]]<br />[[John Rawlinson (footballer and MP)|John Rawlinson]]
}}
{{S-end}}
{{Copley Medallists 1901-1950}}
{{De Morgan Medallists}}
{{Lucasian Professors of Mathematics}}

{{Authority control}}

{{DEFAULTSORT:Larmor, Joseph}}
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