Joseph Larmor

Sir Joseph Larmor

In 1903 he was appointed Lucasian Professor of Mathematics at Cambridge, a post he retained until his retirement in 1932. He never married.^[8] He was knighted by King Edward VII in 1909.

Motivated by his strong opposition to 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. He remained in parliament until the 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 the honorary Doctor of Laws (LLD) from the University of Glasgow in June 1901.^[9][10] 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.^[11][12][13] He was awarded the Poncelet Prize for 1918 by the French Academy of Sciences.^[14] Larmor was a Plenary Speaker in 1920 at the ICM at Strasbourg^[15][16] 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.^[17]

Work

Larmor proposed that the

conduction (but was not part of the atom). Larmor calculated the rate of energy radiation from an accelerating electron. Larmor explained the splitting of the spectral lines in a magnetic field by the oscillation of electrons.^[18]

Larmor also created the first solar system model of the atom in 1897.^[19]

In 1919, Larmor proposed sunspots are 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.”^[20]

Discovery of Lorentz transformation

Parallel to the development of Lorentz ether theory, Larmor published an approximation to the Lorentz transformations in the Philosophical Transactions of the Royal Society in 1897,^[21] namely ${\displaystyle x_{1}=x\epsilon ^{\frac {1}{2}}}$ for the spatial part and ${\displaystyle dt_{1}=dt^{\prime }\epsilon ^{-{\frac {1}{2}}}}$ for the temporal part, where ${\displaystyle \epsilon =\left(1-v^{2}/c^{2}\right)^{-1}}$ and the local time ${\displaystyle t^{\prime }=t-vx/c^{2}}$. He obtained the full Lorentz transformation in 1900 by inserting ${\displaystyle \epsilon }$ into his expression of local time such that ${\displaystyle t^{\prime \prime }=t^{\prime }-\epsilon vx^{\prime }/c^{2}}$, and as before ${\displaystyle x_{1}=\epsilon ^{\frac {1}{2}}x^{\prime }}$ and ${\displaystyle dt_{1}=\epsilon ^{-{\frac {1}{2}}}dt^{\prime \prime }}$.^[22] 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

• 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.
• Larmor, J. (1897). "A Dynamical Theory of the Electric and Luminiferous Medium. Part III. Relations with Material Media". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 190: 205–493.
  doi:10.1098/rsta.1897.0020
  .
• 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.
• Larmor, J. (1900), Aether and Matter , Cambridge University Press; Containing the Lorentz transformations on p. 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. 2, vol. 1 (1904), pp. 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 — II" (read 13 Nov. 1919), Proceedings of the London Mathematical Society, Ser. 2, vol. 19 (1921), pp. 169–80.
• 1924, "On Editing Newton", Nature.
• 1927, "Newtonian time essential to astronomy", Nature.
• 1929, Mathematical and Physical Papers. Cambridge Univ. Press.^[23]
• 1937, (as editor), Origins of Clerk Maxwell's Electric Ideas as Described in Familiar Letters to William Thomson. Cambridge University Press.^[24]

Larmor edited the collected works of

• 
  Title page to a 1900 copy of "Aether and Matter"
• 
  First page of the preface to "Aether and Matter"
• 
  First page of "Aether and Matter"

See also

Wikisource has original works by or about:
Joseph Larmor

• Quotations related to Joseph Larmor at Wikiquote
• History of Lorentz transformations
• Dynamo theory
• Larmor precession
• Larmor (crater)

References