Pieter Zeeman (25.05.1865-9.10.1943) was a Dutch physicist and a member of the Royal Netherlands Academy of Arts and Sciences. He was born in Zonnemaire. He graduated from the University of Leiden (1890), where he taught. From 1897 he worked at the University of Amsterdam (professor from 1900 and director of the Physical Institute from 1908).
His research was in the field of optics, magneto-optics and atomic spectroscopy. In 1896 he discovered the phenomenon of the splitting of spectral lines under the influence of a magnetic field (the Zeeman effect) (Nobel Prize, 1902). He measured (1914 — 15) the speed of light in a rapidly moving rod and proved experimentally (1917), with high accuracy, the equality of inertial and gravitational mass. He determined the specific electric charge. He developed a method of measuring the absorption coefficient of electromagnetic waves. He studied Brownian motion. The B. Franklin Medal.