Scottish physicist (1831–1879) whose equations united electricity, magnetism, and light as a single electromagnetic phenomenon. Maxwell gave Faraday's experimental intuitions rigorous mathematical form, then found that his equations implied waves traveling at the speed of light — from which he concluded that light is an electromagnetic wave. The theory predicted a whole spectrum of invisible radiation, confirmed by Hertz in 1887. He also helped found statistical mechanics and made the first durable color photograph. Ranked alongside Newton and Einstein, he stands as one of the greatest physicists who ever lived.
For two thousand years, light was its own mystery, with no known link to anything else in nature. Then in the 1860s a quiet Scotsman writing equations about electric and magnetic fields noticed that his formulas predicted a wave, and that the wave's speed came out almost exactly equal to the measured speed of light. The match was too close to be chance. James Clerk Maxwell drew the only conclusion he could: light itself is a kind of electromagnetism. Light is electricity and magnetism in motion, a ripple in the same field that makes a magnet pull and a wire spark.