Two newly discovered photographs of Einstein's 1934 lecture derivation of the energy-mass equivalence, popularly written as , are analyzed for clues as to how the only visually documented blackboard lecture of his famous equation progressed. A previous analysis is supplemented with the new information.
References
The others are all variations of this pose with minor changes; apparently each was taken by a different photographer from the three Pittsburgh newspapers at the time. See our 2007 article.
Many attempts to find an original photograph (or hopefully the negative) from the defunct Pittsburgh newspaper proved futile. See our 2007 article, p. 983, note 3.
Both photographs in this paper are reproduced courtesy of The Jacob Rader Marcus Center of the American Jewish Archives, in Cincinnati, Ohio.
See Note #2 (above). (1935), p. 226 or (1999), p. 41. After Eq. (1), Einstein writes: “The sums on the left sides of these equations depend, therefore, only on the velocity u′ of the pair referred to the special system K′ and on the relative velocity v of K′ with respect to K, not however on the direction in which the particles are moving.”
Equations [1E] are:
For the details on this, see our forthcoming book on Einstein's blackboards.
