The Nobel Prize in Physics 1919 Award Ceremony Speech
Presentation Speech by Dr. Å.G. Ekstrand, President of the Royal
Swedish Academy of Sciences, on June 1, 1920 Ladies and
Gentlemen.* The Royal Academy of Sciences has decided to award
the Nobel Prize in Physics for 1919 to Dr. Johannes Stark,
professor in the University of Greifswald, for his discovery of
the Doppler effect in canal rays and of the splitting of
spectral lines in electric fields. It is only rarely that the
study of a physical phenomenon has led to such a brilliant
series of important discoveries as that which follows the
conducting of an electrical current through a rarefied gas. As
long ago as 1869 Hittorf discovered that if a low pressure is
set up in a discharge tube, rays are emitted from the negative
electrode, the so-called cathode. Although invisible to the eye,
they can nevertheless be observed through certain effects
peculiar to them. The continued study of these cathode rays, in
which Lenard in particular earned great merit, showe