James Clerk Maxwell

James Clerk Maxwell was a Scottish physicist and mathematician whose theory of electromagnetism showed that electricity, magnetism and light are aspects of a single phenomenon. Working in Aberdeen, London and Cambridge in the mid-19th century, he also helped found statistical mechanics, made the first colour photograph and predicted the existence of radio waves. Many physicists rank him alongside Newton and Einstein.

Maxwell was born in Edinburgh, at 14 India Street, on 13 June 1831, the son of John Clerk Maxwell, an advocate from a landed family. He grew up at Glenlair, a house his parents had built on the family estate in Kirkcudbrightshire, and as a small child was famous for asking how everything worked. His mother died of abdominal cancer in December 1839, when he was eight.

At ten he was sent to the Edinburgh Academy, where his country clothes and Galloway accent earned him the nickname "Daftie". At 14 wrote a paper on drawing oval curves with string that was read to the Royal Society of Edinburgh on his behalf. In 1847 he entered the University of Edinburgh, where experiments with polarised light in strained gelatine led him to the technique now called photoelasticity.

In 1850 Maxwell moved to the University of Cambridge, soon transferring from Peterhouse to Trinity College. He graduated in mathematics in 1854 as Second Wrangler and shared the Smith's Prize. Using spinning tops painted in different colours, he showed how red, green and blue light combine, and set out the principles of colour mixing. The same year his paper on Michael Faraday's lines of force began his long engagement with electricity and magnetism.

In 1856 Maxwell took up the natural philosophy chair at Marischal College, Aberdeen, some 15 years younger than any colleague. There he tackled the stability of Saturn's rings, the subject of the 1857 Adams Prize. He proved that neither a solid nor a fluid ring could survive and concluded that the rings must consist of countless small particles, winning the prize in 1859. Voyager observations in the 1980s confirmed his conclusion. In 1858 he married Katherine Mary Dewar, daughter of the college principal.

When Marischal merged with King's College in 1860 to form the University of Aberdeen, Maxwell lost his post. After surviving smallpox, he moved to King's College London as its professor of natural philosophy, the most productive period of his life. At the Royal Institution he came to know the elderly Michael Faraday. In 1861 he showed the first colour photograph, a tartan ribbon taken through red, green and blue filters.

His papers On Physical Lines of Force (1861–62) and A Dynamical Theory of the Electromagnetic Field (1865) argued that electric and magnetic fields spread through space as waves travelling at the speed of light, and that light itself is such a wave. He also developed the statistical description of gas molecules now called the Maxwell–Boltzmann distribution.

In 1865 Maxwell resigned and returned to Glenlair. There he wrote most of A Treatise on Electricity and Magnetism, published in 1873, along with a paper on governors, the speed-regulating devices of steam engines, which laid the groundwork for control engineering. In 1871 Cambridge brought him back as its first Cavendish Professor of Physics and oversaw the building of the Cavendish Laboratory.

He fell ill in 1879 and died of abdominal cancer in Cambridge on 5 November that year, aged 48, the same age and illness as his mother. He was buried at Parton Kirk in Galloway, near his childhood home.

Oliver Heaviside later reduced Maxwell's equations to the four now taught to every physics student. The difficulties his theory raised about the supposed luminiferous aether helped inspire Albert Einstein to formulate special relativity, and Einstein called Maxwell's work the most profound and fruitful in physics since Isaac Newton.

Maxwell lived and worked entirely within the United Kingdom, in Scotland and England. Our 1815 and 1878 maps bracket his lifetime, the latter showing Britain at the height of its Victorian power, with London as its capital.