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Archives Biographies: James Clerk Maxwell

James Clerk Maxwell was a Scottish theoretical physicist and mathematician who did pioneering work in electromagnetism and the kinetic theory of gases. 

Early Life

Seated portrait of James Clerk Maxwell at table with electrical equipment. From a portrait by R.H. Campbell, 1929.

He was born on 13 November 1831 in Edinburgh, to John Clerk Maxwell, and Frances Maxwell (née Cay). As a child Maxwell proved to have an insatiable curiosity in the world around him. Recognising his intellectual potential, his father sent him to the prestigious Edinburgh Academy in 1841. Here Maxwell made life-long friends with Lewis Campbell and Peter Guthrie Tait, who would themselves go on to become notable scholars. 

While at the Academy, aged only 14, Maxwell wrote his first academic paper, entitled ‘Oval Curves’, which was presented to the Royal Society of Edinburgh. In 1847 Maxwell went on to study at the University of Edinburgh, where two more of his papers were presented to the Royal Society. 

In 1850, he went on to study mathematics at Trinity College, Cambridge, where he graduated as Second Wrangler in 1854. He was made a Fellow of Trinity in 1855, but just a year later the Chair of Natural Philosophy at Marischal College, Aberdeen, became vacant and he successfully applied.

Marischal College, Aberdeen

While at Marischal, Maxwell focused on a study of the planet Saturn's rings, the nature of which was much debated. In 1859 he submitted a paper which argued that stability of the rings could be achieved only if they consisted of numerous small solid particles. For this Maxwell won the Adams Prize, awarded by Cambridge University.

King’s College London

In 1860 Maxwell became the Chair of Natural Philosophy at King’s College London, where he made progress in producing the world’s first colour photograph, for which he was awarded the Rumford Medal by the Royal Society of London the same year. 

While at King’s he also became involved with investigating the kinetic theory of gases. While this subject had already been extensively researched by the likes of James Joule and Rudolf Clausius, Maxwell’s experiments made great advances in the laws of gaseous friction. In particular in 1866 he developed a formula called the Maxwell distribution, which gives the fraction of gas molecules moving at a specified velocity at any given temperature. In the kinetic theory, temperatures and heat involve only molecular movement. 

This approach generalized the previously established laws of thermodynamics and explained existing observations and experiments in a better way than had been achieved previously.

Electromagnetism

However, arguably Maxwell's most important achievement was his extension and mathematical formulation of Michael Faraday's theories of electricity and magnetic lines of force. In his research, conducted between 1864 and 1873, Maxwell showed that a few relatively simple mathematical equations could express the behaviour of electric and magnetic fields and their interrelated nature; that is, an oscillating electric charge produces an electromagnetic field. These four partial differential equations first appeared in fully developed form in his work Electricity and Magnetism published in 1873.

Cavendish Laboratory

In 1871 Maxwell became heavily involved in the development of the Cavendish Laboratory at Cambridge University, when he became the first Cavendish Professor of Physics. During the 1870s he also spent much time editing the papers of Henry Cavendish. Cavendish was the great-uncle to William Cavendish, 7th Duke of Devonshire and Chancellor of the University of Cambridge, who had donated funds for the setting up of the Laboratory. 

Henry Cavendish (1731-1810) was a scientist noted for his discovery of hydrogen and experiments in measuring the density of the earth. After his death he left twenty packages of manuscript material, which Maxwell transcribed and edited. The result of this work was the publication of The Electrical Researches of the Honorable Henry Cavendish,in 1879.

Legacy

Maxwell died in Cambridge of abdominal cancer on 5 November 1879 at the age of 48. His legacy was extensive, and his name being honoured in a number of ways, such as the maxwell  (Mw), a compound derived CGS unit measuring magnetic flux, the Maxwell Gap in the Rings of Saturn and the James Clerk Maxwell Telescope, the largest submillimeter-wavelength astronomical telescope in the world, with a diameter of 15 metres.

The Clerk Maxwell Lecture

The Clerk Maxwell Lecture was initiated by the Institution of Electronics and Radio Engineers (IERE) in 1951. It was retained after the merger with the IEE as a "most prestigious lecture event" to be held when suitable speakers and subjects arose (approximately every third year). Now it is in the IET's Prestige Lecture Series and is run every year on a power related subject.