1 8 8 D O C U M E N T 4 9 J U N E 1 9 2 0
colleagues are sufficiently well informed on the basic contours of relativity theory,
so there does not seem to be any need for the talk you are proposing. By contrast,
it might be of some interest to organize a general discussion on the subject. To such
an event I would gladly come and answer all questions posed to me. However, at-
tention must somehow be given to have the questions screened in advance so that
the discussion not be disturbed by low-quality questions. In case you think my sug-
gestion is a good one, please do send me further information.
In utmost respect, yours very truly.
49. From Hendrik A. Lorentz
Haarlem, 9 June 1920
Dear Colleague,
After having already briefly mentioned it to you verbally, I now have the plea-
sure of inviting you, in the name of the science
committee[1]
of the “Solvay Inter-
national Institute of Physics” [The committee members are currently [Edmond] van
Aubel (Ghent), W. H. Bragg, [Léon] Brillouin, Mrs. [Marie] Curie, [Heike] Kamer-
lingh Onnes, [Martin] Knudsen, Lorentz, [Augusto] Righi, [Ernest] Rutherford], to
the “Physics Conference” to take place next spring in
Brussels[2]
and to ask you to
prepare a report on the effect predicted by you and observed together with de
Haas[3]
(Ampère’s molecular currents), and its
consequences.[4]
Should you want
to participate again in this little congress, you would be doing us a great
favor.[5]
The meeting will begin on April 1st and will last one short week. As a general
theme we have chosen the electron theory and its most important applications,
atomic emissions and radiation phenomena (not black-body radiation); it is our in-
tention to prompt an exchange of ideas specifically on the fundamental concepts,
general ideas, and still-open questions. We thus would like to limit the discussion,
e.g., on Bohr’s theory, to the fundamentals and the simpler cases, without delving
too deeply into the details of complex atomic structures.
Division of the material, indicating the gentlemen whom we are going to ask to
draw up reports:
1. General topics on the theory of electrons. Consequences of the theory and
difficulties. Lorentz.
2a.
Structure of atoms. Constitution of the nucleus. Isotopes. Rutherford.
2b.
A few things on quantum theory. Specifically, your photoelectric rule. De
Broglie.[6]
3. Bohr’s theory. Electron arrangement within the atom.
Bohr.[7]
4a.
Electrons and magnetism. Gyroscopic effects. Einstein.
4b.
Attempts to explain para- and diamagnetism. Magnetism at low
temperatures. Kamerlingh Onnes or
Langevin.[8]