It
is often said that the electron was discovered in 1897 by J.J. Thomson.
That is an oversimplification. The idea of an atomic unit of charge was
probably formulated for the first time by Faraday in connection with his
experiments on electrolysis. But this idea did not easily fit in with the
notion of an electromagnetic field. Hendrik Antoon Lorentz modified and
completed Maxwell's theory of electromagnetism. In his theory the electric
and magnetic properties of matter are interpreted in terms of the motion
of charged atomic particles. A magnetic field exerts a force on these
particles, now called the "Lorentz force". In 1896 Pieter Zeeman,
then an experimental physicist in Leiden, made a surprising discovery: the
splitting of spectral lines by a magnetic field. Lorentz was able to
explain the new phenomenon with his electron theory. He concluded that the
radiation of atoms consisted of negatively charged particles with a very
small mass. In 1902 the two researchers jointly received the Nobel Prize
for Physics.H.B.G. Casimir, Haphazard Reality (Harper & Row, New York, 1983)
Information provided by: http://www.ilorentz.org