James Clerk Maxwell
James Clerk Maxwell unified electricity, magnetism and light into a single theory, and is generally ranked with Newton and Einstein. Born in Edinburgh in 1831 into a Scottish landowning family, he grew up at Glenlair in Galloway, was an insatiable questioner as a child, and published his first paper, on a method of drawing oval curves, at fourteen. He studied at Edinburgh and then Cambridge, where he was second wrangler. His first major work explained the rings of Saturn in 1859, proving that they could be neither solid nor liquid without breaking up, and must consist of countless small particles — confirmed by Voyager more than a century later. He then developed the kinetic theory of gases with Ludwig Boltzmann, producing the Maxwell-Boltzmann distribution of molecular speeds. This introduced statistical reasoning into physics, a fundamental shift: laws that hold for populations rather than for individual particles. His central achievement came in the 1860s. He took Michael Faraday's experimental picture of lines of force and turned it into mathematics, arriving at a set of equations describing electric and magnetic fields. They implied waves propagating at a speed he calculated from purely electrical measurements — and it matched the measured speed of light. He concluded that light is an electromagnetic wave, and that other wavelengths must exist. Heinrich Hertz produced radio waves in 1887, eight years after Maxwell's death. He also produced the first colour photograph in 1861, demonstrating three-colour separation, and worked on control theory and structural engineering. He was the first Cavendish Professor at Cambridge, designing the laboratory. He died of abdominal cancer in 1879, aged forty-eight, the same disease and age as his mother.
- Lived: 1831 CE – 1879 CE
- Nationality: British
- Roles: physicist, mathematician
