James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician who was responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and light as different manifestations of the same phenomenon. Maxwell's equations for electromagnetism achieved the second great unification in physics, where the first one had been realised by Isaac Newton. Maxwell was also key in the creation of statistical mechanics.
Maxwell graduated from Trinity College, Cambridge, in 1854, where he earned distinction in mathematics and the Smith's Prize. He remained at Cambridge briefly, publishing early mathematical work and investigations into optics, particularly the principles of colour combination and colour-blindness. He later held the Chair of Natural Philosophy at Marischal College in Aberdeen, where he studied the rings of Saturn and correctly proposed that they were composed of numerous small particles, work that earned him the Adams Prize in 1859. During this time he married Katherine Mary Dewar, who assisted him in his laboratory work. From 1860 to 1865, he served as the Professor of Natural Philosophy at King's College London, where he developed his theory of electromagnetic fields. His publication of "A Dynamical Theory of the Electromagnetic Field" in 1865 demonstrated that electric and magnetic fields travel through space as waves moving at the speed of light, proposing that light is an undulation in the same medium that is the cause of electric and magnetic phenomena. His unification of light and electrical phenomena led to his prediction of the existence of radio waves.
Maxwell was the first to derive the Maxwell–Boltzmann distribution, a statistical means of describing aspects of the kinetic theory of gases, which he worked on sporadically throughout his career. He presented the first durable colour photograph in 1861, and showed that any colour can be produced with a mixture of any three primary colours, those being red, green, and blue, the basis for colour television. He worked on analysing the rigidity of rod-and-joint frameworks (trusses) like those in many bridges. He devised modern dimensional analysis and helped to establish the CGS system of measurement. He was the first to recognize chaos, and the first to emphasize the butterfly effect. His 1863 paper On Governors serves as an important foundation for control theory and cybernetics, and was also the earliest mathematical analysis on control systems. In 1867, he proposed the thought experiment known as Maxwell's demon, which challenges how information affects entropy in thermodynamics. In his seminal 1867 paper On the Dynamical Theory of Gases he introduced the Maxwell model for describing the behavior of a viscoelastic material and originated the Maxwell-Cattaneo equation for describing the transport of heat in a medium.
In 1871, Maxwell returned to Cambridge as the first Cavendish Professor of Physics, overseeing the construction of the Cavendish Laboratory. As a result of his work he is regarded as a founder of the modern field of electrical engineering. His discoveries helped usher in the era of modern physics, laying the foundations for such fields as relativity, also being the one to introduce the term into physics, and quantum mechanics.
James Clerk Maxwell was born on 13 June 1831 at 14 India Street, Edinburgh, to John Clerk Maxwell of Middlebie, an advocate, and Frances Cay, daughter of Robert Hodshon Cay and sister of John Cay. (His birthplace now houses a museum operated by the James Clerk Maxwell Foundation.) His father was a man of comfortable means of the Clerk family of Penicuik, holders of the baronetcy of Clerk of Penicuik. His father's brother was the 6th baronet. He had been born "John Clerk", adding "Maxwell" to his own after he inherited (as an infant in 1793) the Middlebie estate, a Maxwell property in Dumfriesshire. James was a first cousin of both the artist Jemima Blackburn (the daughter of his father's sister) and the civil engineer William Dyce Cay (the son of his mother's brother). Cay and Maxwell were close friends and Cay acted as his best man when Maxwell married.
Maxwell's parents met and married when they were well into their thirties; his mother was nearly 40 when he was born. They had had one earlier child, a daughter named Elizabeth, who died in infancy.
When Maxwell was young his family moved to Glenlair, in Kirkcudbrightshire, which his parents had built on the estate which comprised 1,500 acres (610 ha). All indications suggest that Maxwell had maintained an unquenchable curiosity from an early age. By the age of three, everything that moved, shone, or made a noise drew the question: "what's the go o' that?". In a passage added to a letter from his father to his sister-in-law Jane Cay in 1834, his mother described this innate sense of inquisitiveness:
He is a very happy man, and has improved much since the weather got moderate; he has great work with doors, locks, keys, etc., and "show me how it doos" is never out of his mouth. He also investigates the hidden course of streams and bell-wires, the way the water gets from the pond through the wall....
Recognising the boy's potential, Maxwell's mother Frances took responsibility for his early education, which in the Victorian era was largely the job of the woman of the house. At eight he could recite long passages of John Milton and the whole of the 119th psalm (176 verses). Indeed, his knowledge of scripture was already detailed; he could give chapter and verse for almost any quotation from the Psalms. His mother was taken ill with abdominal cancer and, after an unsuccessful operation, died in December 1839 when he was eight years old. His education was then overseen by his father and his father's sister-in-law Jane, both of whom played pivotal roles in his life. His formal schooling began unsuccessfully under the guidance of a 16-year-old hired tutor. Little is known about the young man hired to instruct Maxwell, except that he treated the younger boy harshly, chiding him for being slow and wayward. The tutor was dismissed in November 1841. James' father took him to Robert Davidson's demonstration of electric propulsion and magnetic force on 12 February 1842, an experience with profound implications for the boy.
In 1841, at age ten, Maxwell was sent to the prestigious Edinburgh Academy. He lodged during term times at the house of his aunt Isabella. During this time his passion for drawing was encouraged by his older cousin Jemima. The young Maxwell, having been raised in isolation on his father's countryside estate, did not fit in well at school. The first year had been full, obliging him to join the second year with classmates a year his senior. His mannerisms and Galloway accent struck the other boys as rustic. Having arrived on his first day of school wearing a pair of homemade shoes and a tunic, he earned the unkind nickname of "Daftie". He never seemed to resent the epithet, bearing it without complaint for many years. Social isolation at the Academy ended when he met Lewis Campbell and Peter Guthrie Tait, two boys of a similar age who were to become notable scholars later in life. They remained lifelong friends.
Maxwell was fascinated by geometry at an early age, rediscovering the regular polyhedra before he received any formal instruction. Despite his winning the school's scripture biography prize in his second year, his academic work remained unnoticed until, at the age of 13, he won the school's mathematical medal and first prize for both English and poetry.
Maxwell's interests ranged far beyond the school syllabus and he did not pay particular attention to examination performance. He wrote his first scientific paper at the age of 14. In it, he described a mechanical means of drawing mathematical curves with a piece of twine, and the properties of ellipses, Cartesian ovals, and related curves with more than two foci. The work, of 1846, "On the description of oval curves and those having a plurality of foci" was presented to the Royal Society of Edinburgh by James Forbes, a professor of natural philosophy at the University of Edinburgh, because Maxwell was deemed too young to present the work himself. The work was not entirely original, since René Descartes had also examined the properties of such multifocal ellipses in the 17th century, but Maxwell had simplified their construction.