x x x v i I N T R O D U C T I O N T O V O L U M E 1 2
(Einstein 1922c [Vol. 7, Doc. 71]). Contemporary transcripts of notes by auditors
are available for the first two, more popular Princeton lectures (Vol. 7, Appendix
C). Abstracts for the three more technical lectures in Princeton are presented in this
volume (Appendix E), together with auditors’ notes for some of his other lectures
of the year. Evidence of their content, if not of the actually spoken word, is
available for the lectures at CCNY (Appendix C), and for those at the University of
Chicago and the Parker School (Appendix D). In America, as elsewhere, Einstein
talked about relativity theory in various degrees of technical detail, adjusting con-
tent and terminology to the scientific background of his audience. The first CCNY
lecture differs from subsequent ones in that Einstein addressed not only relativity
theory, but quantum theory as well. At CCNY, he devoted two lectures to special
relativity and a third to general relativity, the material in all three corresponding to
the two less technical lectures with which he would begin his Princeton series. The
fourth lecture at CCNY was in part a discussion of the contention in his Leyden
inaugural lecture of 1920, Ether and the Theory of Relativity (Einstein 1920j)
[Vol. 7, Doc. 38]), that the general theory could be construed as an ether theory, al-
beit one shorn of the objectionable absolute a priori characteristics of the old lu-
miniferous ether, but nevertheless a substantivalist theory to the extent that
spacetime itself played a key role in determining the motion of matter. The rest of
the fourth lecture was devoted to an analysis of the meaning of electromagnetic ra-
diation in quantum theory, touching on the issues of production and absorption of
light as described by the two rival particle (discrete) and wave (continuous) theories
of light. This was not only a problem with which Einstein was grappling at this
time, but his audience also welcomed it with great interest. Members of the CCNY
Research Committee proposed that Einstein publish specifically this last lecture on
radiation and quantum theory (Calendar entry of 23 April).
The suggestion was not taken up, nor did Einstein talk about this quantum topic
in subsequent lectures. It played no role in any of the three lectures given at the Uni-
versity of Chicago at the invitation of its president, Harry Pratt
Judson.[33]
Earlier,
Carl Beck, a noted Chicago physician, who had been warmly recommended by
Felix Ehrenhaft (Doc. 36), had already offered his assistance if and when Einstein
were to visit the United States on an academic lecture tour. Einstein expressed the
desire to meet the “American world of science,” and asked whether Beck could help
him meet Chicago physicists (Doc. 115). Prominent among these were Albert A.
Michelson, Robert A. Millikan, and Henry G. Gale. Although Michelson, of whom
Einstein thought highly (see, e.g., Doc. 103), was traveling in Europe (Docs. 107
and 187), he did meet Millikan, who had returned by then from the just concluded
Solvay Congress (Doc. 163).