D O C U M E N T S 2 2 8 , 2 2 9 S E P T E M B E R 1 9 2 1 1 5 3
228. To James Franck
[Berlin, 4 September 1921]
…
I consider the application by Klein and Rosseland correct, whether or not either
electrons or atoms are involved in collisions with an excited
atom.[1]
It is simply a
reversal of the effect of their impact. But the consequences concerning the momen-
tum characteristics of the radiation cannot be modified by this aspect, because the
collisions can be arbitrarily rare. The radiative influence on its own must yield the
same mean kinetic energy of the atoms as the collisions on their own; otherwise the
thermal equilibrium goes out of kilter when both act at the same time …
229. From Ludwik Silberstein
Rochester, N.Y., 129 Seneca Parkway, 4 September 1921
Dear Professor Einstein,
Two days ago I arrived here again, at my permanent residence—and workplace,
and (last not least) am with my wife and children, after ending my “course” (43 lec-
tures on relat., gravit., & el[ectro]m[a]gn[e]t.) at the Ryerson Laboratory on 1
Sept.[1]
Your candid letter of August 10 reached me a day before my departure from
Chicago[2]
and so I was able to read it immediately to my friends there and show it
to them, namely to Millikan,
Gale[3]
(who is going to transmit it verbatim to Prof.
Michelson, now at Mount
Wilson),[4]
and many others, all of whom I requested
inform their colleagues and their wives of its content.
I cannot well put into words how profoundly pleased Dr. Gale and Dr. Millikan
were about your letter, morally as well as emotionally; for they admired and loved
you from the start; in any event, they did not expect anything other than a repudia-
tion of the newspaperman fabrication—but they were happy because they saw how
much you took the matter to heart and saw therein the best proof that you fully
reciprocate the sympathy of your American admirers. In short, the matter is com-
pletely settled and all Chicago professors’ disposition toward you is just as friendly,
indeed more so, than before these “mean” Berlin calumnies.