494 APPENDICES
be associated with work on unified field theory and that he believed his career
would best be furthered by independent work. I knew him during the last years
of his life, a gentle and somewhat diffident figure with an office on the third floor
in Fuld Hall. d. 1948, Princeton.
- Richard Chase Tolman. b. 1881, West Newton, Massachusetts. PhD in
physical chemistry in 1910 with Arthur Noyes. Professor at California Institute
of Technology 1922. Author of two books on relativity theory [Tl, T2]. During
Einstein's first visit to California, Tolman collaborated with Ehrenfest and Podol-
sky on a study of the gravitational field produced by light [E46] and with Einstein
and Podolsky on a less-than-successful study of the measurement problem in
quantum mechanics [E47]. d. 1948, Pasadena, California.
- Willem de Sitter, b. 1872, Sneek, Holland. PhD in Groningen with Jaco-
bus Kapteyn. Proposed the 'de Sitter universe' in 1917. Director of the Leiden
astronomical observatory 1919-34. During Einstein's second visit to California,
he published a joint note with de Sitter [E48] in which a cosmologically flat uni-
verse is proposed (without cosmological term and with zero pressure), d. 1934,
Leiden.
- Boris Podolsky. b. 1896, Taganrog, Russia. Emigrated to the United
States in 1913. PhD with Paul Epstein at CalTech 1928. Podolsky met Einstein
in Pasadena in 1931 and collaborated with him and Tolman. He was in Charkov
in the early 1930s where he worked with Fock and Dirac on quantum electro-
dynamics. He was a member of The Institute for Advanced Study in 1934-35,
when the Einstein-Podolsky-Rosen collaboration took place [E49] (Section 25c).
In this paper, the term wave function is used. I was sure that Einstein had not
done the actual writing, since he would invariably use the expression psi-function
instead. Nathan Rosen told me that the paper was written by Podolsky. Later
Podolsky became research professor at the Xavier University in Cincinnati [D2].
d. 1966, Cincinnati.
- Nathan Rosen, b. 1909, Brooklyn, New York. ScD at MIT in 1932.
Rosen wrote his master's thesis on distant parallelism and then went to Princeton
to work on theoretical molecular physics.* While in Princeton, he solicited Ein-
stein's opinion on his master's thesis. This contact led to a period of collaboration.
Rosen was a member of The Institute for Advanced Study in 1934-5. The first
joint paper was the Einstein-Podolsky-Rosen article, the main idea of which
came from Rosen. This was followed two months later by a paper on singularity-
free solutions of the combined gravitational and electromagnetic field [E50]. In
1936 they published a note on the general relativistic two-body problem [E51] and
in 1937 a paper on cylindrical gravitational waves [E52].
In the course of working on this last problem, Einstein believed for some time
that he had shown that the rigorous relativistic field equations do not allow for the
existence of gravitational waves [II, S2]. After he found the mistake in the argu-
*I am indebted to Nathan Rosen for telling me of his experiences.
