Larmor, Joseph

by Patricia M. Byrne and Denis Weaire

Larmor, Joseph (1857–1942), mathematical physicist, was born 11 July 1857 at Ballycarrickmaddy, Magheragall, Co. Antrim, eldest among five sons and two daughters of Hugh Larmor, well-to-do farmer turned grocer, and his wife Hannah, eldest daughter of Joseph Wright of Stoneyford, Co. Antrim. The family moved to Belfast around 1863, probably due to the wishes of Hannah to give her children a better education; she was highly ambitious for their intellectual advancement. They lived at Adela Street, off the Antrim Road, where Hugh opened a grocery shop. He still kept the farm in Ballycarrickmaddy. Joseph went to national school in Eglington Street, where he was remembered as 'good at all his lessons' (Morton, 1944). In 1869, at the age of 12, he attended the Royal Academical Institution, where the mathematics master, R. C. J. Nixon, took an interest in him. A thin and delicate boy, he had a precocious ability in mathematics and classics. At the age of 14 he entered QCB, obtaining a double first in the scholarship exam and graduating with high honours at 17 (BA, 1874). He was seen as fortunate in having the inspiring mathematics professor, John Purser, who was incomparable as a teacher but published little. After graduating Larmor remained in Queen's for a further year as senior scholar in mathematics, before receiving his MA (1875).

In 1877 he entered St John's College, Cambridge, after suffering ill health for the previous year. He also took a degree by examination with London University, winning the Neil Arnott medal for the best mathematician of the year (1877). In 1880 he was senior wrangler in the mathematical tripos (beating J. J. Thomson into second place), was awarded the Smith prize, and was elected fellow of St John's. That year he was also appointed professor of natural philosophy in QCG, where he spent five happy years. Initiating physical practical classes, he purchased modern physical apparatus such as a Wheatstone microphone and phonograph. He also wrote his first papers there, including 'Least action as the fundamental formulation in dynamics and physics' (1884), devoted to a principle central to his scientific thought.

He somewhat reluctantly returned to St John's in 1885 as a lecturer, but continued his own researches. His teaching style as well as his writing had the reputation for being obscure but stimulating. By 1892 he had published over thirty papers in applied mathematics and theoretical physics, for which he was elected FRS, later becoming secretary (1901–12) to the mathematical and physics section. His most important work, 'A dynamical theory of the electric and luminiferous medium', was published in three instalments in the Philosophical Transactions of the Royal Society (1894, 1896, 1897), and collected later as Aether and matter (1900). In 1903 he was appointed to the Lucasian professorship, the chair of Newton, on the death of Sir George Stokes (qv). He remained there for almost thirty years. He represented Cambridge University in Westminster as a unionist MP (1911–22), where his major concern was for education and the universities. He was fond of telling the story that he had voted for the abolition of the carrying of a red flag in front of motor cars, and had been haunted by remorse ever since.

From about 1890 he was a prominent member of the Maxwellians, led by George F. Fitzgerald (qv). His views on the ether of space and its relation to Maxwell's electromagnetic theory contributed to an intense debate. His particular contribution lay in the incorporation of the charged particle that G. J. Stoney (qv) had named the 'electron'. Rather than seeing it as an added ingredient of Maxwellian theory, he regarded it as a property of the ether itself, which gave rise to the quip that his book was on 'Aether and no matter'. His description of the effects of a magnetic field on an electron has secured him a lasting place in the terminology of physics (Larmor frequency, Larmor precession, etc.). This work was essential in the interpretation of the Zeeman effect (see Thomas Preston (qv)), which provided early evidence of the reality of the electron.

Larmor is also associated with various aspects of special relativity, particularly time dilation, which neatly complements his colleague Fitzgerald's conception of length contraction. Indeed, his electrodynamic theory contained the main elements of relativity theory, including the Lorentz transformations. He is not unique in having presaged much of the theory well before Einstein, but deserves greater credit than he is generally given.

In his later years he continued to publish research papers, including such subjects as the bending of radio waves around the earth (1924) and the irregularities of the rotation of the earth (1906, 1915); most of his papers are found in his Mathematical and physical papers (1929). He held in great esteem the work of certain Irish mathematicians, in particular Sir William Rowan Hamilton (qv) and George F. Fitzgerald. He edited the collected papers of Fitzgerald, of Lord Kelvin (William Thomson (qv)), and of Kelvin's elder brother James Thomson (qv). His interest in the history and development of scientific thought led him to write a biography of Lord Kelvin (Proceedings of the Royal Society, lxxxi a (1908), pp i–lxxvi), of which he was particularly proud.

A member of many academic bodies in the UK and abroad, including hon. MRIA, he received many honours in his lifetime, including the Royal Society's Royal medal in 1915 and the society's Copley medal in 1921, and was made a corresponding member of the Institut de France. Among his many honorary degrees was an LLD from the University of Glasgow (1901). As an elected member of the London Mathematical Society (1884), he was its treasurer (1892–1912), vice-president (1890, 1891), and president (1914–15), when he received the De Morgan medal. He was knighted in 1909 and received the freedom of Belfast city in 1912.

Neat and dapper in appearance, he was unassuming and easily approachable, but was naturally diffident and did not form close friendships easily. However, his conscientiousness often pushed him into more public social activity. He was especially kind to students from Queen's University and made a point of visiting them on their arrival in Cambridge. His attachment to Ireland was strong, and every year he spent part of his summer holidays there. On his retirement in 1932 at the age of 75 he returned to live in 'Drumadiller', Hollywood, Co. Down, where his four unmarried siblings lived. Despite suffering from pernicious anaemia he continued reading and writing, mostly short articles to Nature on all sorts of subjects, including the physiological potency of dilute medicines relating to his own medical experiences. His last surviving brother died before him, and he was left in the care of an old family servant for his last year. He died 19 May 1942 at Hollywood, Co. Down. He left several bequests to the University of Cambridge, £250 to the RIA to fund the occasional Larmor lecture, and £750 to UCG to fund the Larmor prize for first place in the B.Sc. examination in mathematics, mathematical physics, or experimental physics. The UCG Larmor lecture theatre was named in his honour, and QUB has an annual Larmor lecture.

Renowned as a problem solver, Larmor was the very epitome of the nineteenth-century Cambridge wranglers. Turning his prodigious talents to theoretical physics, as many of them did, he lacked the physical insight of others, but his honoured place among the Maxwellian brotherhood gave him a platform and a source of critical advice that kept his ideas at the heart of a great revolution in physics.