James Clerk Maxwell (1831-1879)

James Clerk Maxwell was a Scottish physicist, best known for developing electromagnetic theory. As a child he was interested in colour and shapes, which attracted him to study mathematics and natural philosophy. He wrote his first scientific paper at the age of 14, which was presented to the Royal Society of Edinburgh on his behalf as he was too young to attend. He studied at the universities of Edinburgh and Cambridge, supplementing this by carrying out his own experiments and studies during summer holidays on his family’s Scottish estate.

Maxwell became Professor of Natural Philosophy at Marischal College, Aberdeen in 1856. While at Aberdeen he studied the dynamics of Saturn’s rings, proposing that they were made up of many small particles rather than being solid. This was confirmed experimentally several decades later.

In 1860, Maxwell took up a post at King’s College, London. Here he developed a kinetic theory of gases, showing that a gas’s temperature depends on the motion of its molecules. This theory, which was independently developed by Ludwig Boltzmann, was an important application of statistics to physical theories, describing the world in terms of probabilities rather than certainties.

His most influential work was on electricity and magnetism. Building on the work of Michael Faraday and others, Maxwell formulated mathematical descriptions of both phenomena in terms of electromagnetic fields. He later calculated that electromagnetic fields travelled at the speed of light - and thus that light itself must be an electromagnetic wave. Maxwell formulated four fundamental equations describing electromagnetic phenomena, which were published in their complete form in A Treatise on Electricity and Magnetism in 1873. His unification of the sciences of electricity, magnetism and optics formed the basis for many developments in theoretical physics.

In 1871, Maxwell was appointed Cavendish Professor of Physics at Cambridge, where he helped to set up the Cavendish Laboratory, which opened in 1874. He died in Cambridge in 1879.