5 1 2 D O C U M E N T 3 3 0 O C T O B E R 1 9 2 4
our joint very cordial invitation to you to spend such time with us this winter as you
can afford to give. Even if you should have to shorten your stay to six weeks we
should be delighted to have you for that length of time and would arrange to pro-
vide the same stipend.
With very cordial regards from Mrs.
and myself, and all the rest of
your friends here, such as Epstein, Bateman, Tolman, Hale, Adams, St. John,
etc., I am
Very cordially yours,
R. A. Millikan
TLS. [17 291]. The letter is addressed “Professor A. Einstein, University of Berlin, Berlin, Germany”
and is written on letterhead “California Institute of Technology Pasadena Norman Bridge Laboratory
Hendrik A. Lorentz and Paul Ehrenfest had visited Caltech in 1922 and 1924, respectively (see
Paul Ehrenfest to Einstein, 4 February 1922 [Vol. 13, Doc. 45], note 5 and Doc. 136).
Louis A. Bauer; Samuel J. Barnett (1873–1956) was an American physicist and research asso-
ciate at Caltech.
Ira S. Bowen (1898–1973) was collaborating with Millikan on spectroscopic research.
Millikan and Bowen had discovered an important analogy between X-ray spectra and optical
spectra, which, however, in some cases seemed to contradict the usual Bohr-Sommerfeld theory. This
is the difficulty Millikan is referring to; the relativistic mass-velocity dependence he mentions here
had been used by Arnold Sommerfeld in his explanation of the fine structure of spectral lines. The
difficulty was eventually resolved through the introduction of the electron spin quantum number. See
Bowen and Millikan 1924 and Millikan and Bowen 1924, 1925; see also the discussion in Mehra and
Rechenberg 1982, pp. 662–665.
Albert A. Michelson.
John C. Merriam (1869–1945) was an American paleontologist; George E. Hale; Walter S.
Adams (1876–1956) was an American astronomer and director of the Mount Wilson Observatory;
Charles E. St. John.
Paul S. Epstein.
See Doc. 298.
Greta E. Millikan (1878–1953).
Harry Bateman (1882–1946) was a British mathematician and Professor of Theoretical Physics,
Mathematics and Aeronautics at Caltech; Richard C. Tolman (1881–1948) was Professor of Physical
Chemistry and Mathematical Physics at Caltech; Stanislaw Loria (1883–1958) was a Polish physicist
and a research associate in physics at Caltech.
330. To Jost Winteler
[Lucerne, 3 October 1924]
Lieber Herr Professor
Hier bin ich mit Michele und
froh beisammen und wir plaudern zusam-
men schier ohne die Jahre zu spüren, die uns die Mutter Zeit auf den Buckel