Pieter Zeeman 1865-1943

Abstract

Pieter Zeeman was born in Zeeland at the mouth of the Scheldt. He was the son of a Lutheran pastor and was educated at the University of Leyden. In 1890, when twenty-five years of age, he was appointed assistant on the physics staff. Among his duties at this time was to prepare lecture experiments for the elementary lectures, which, oddly enough, were given by H. A. Lorentz, the Professor of Theoretical Physics. It appears that these lectures would normally have been given by Kamerlingh Onnes, who was Professor of Experimental Physics and Director of the Laboratory. Onnes threw himself entirely into the organization of his cryogenic researches, which were no doubt very important and very successful, culminating, as they did, in the liquefaction of helium. He contrived to leave much of the work of routine teaching to Lorentz. Zeeman assisted Lorentz; he was set to prepare spectacular experimental demonstrations, such as the piercing of a thick block of glass by a powerful discharge. This, as he told me, did not commend itself to him as an adequate object for the considerable labour involved in drilling holes in the glass for the lead-in wires. This little anecdote struck me as curious, for it did not seem quite in character with what I knew of Lorentz otherwise. Zeeman was privat-docent in the University of Leyden when he made his great discovery, which the world calls the Zeeman Effect, but which he himself modestly referred to as ‘the magnetic splitting of the spectrum lines’. It was made public on 31 October 1896 by communication to the Academy of Science at Amsterdam. The idea that a source of light might be in some way affected by magnetic force was not altogether new. Such an effect was looked for by Faraday in 1862, at the very end of his career as an experimentalist, but the result was negative.