Poynting, John Henry (1852-1914), was a British physicist whose most important research was on the theory of electromagnetism. He described mathematically the direction in which a quantity of electrical energy may move. It is known as the Poynting vector. He also measured the density of Earth and the pressure of light on such bodies as a comet’s tail. Along with the British physicist Joseph J. Thomson, he wrote Textbook of Physics. Poynting was born in Monton, near Manchester, England, on Sept. 9, 1852. He died on March 30, 1914.
