D O C U M E N T S 2 1 5 , 2 1 6 F E B R U A R Y 1 9 2 4 2 1 1
215. To Heinrich Zangger
[Berlin,] 23 February 1924
Dear Zangger,
The Naples people have been inviting me so insistently that I now do have to
come. I am writing you this because I gave you the opposite information a while
ago.[1]
It does seem to be getting somewhat better here, despite much poverty and
unemployment. I am feeling well. I am working on a very daring and, at the same
time, difficult theory.
(Quanta).[2]
It’s not so easy to get at the deeper secrets…
Cordial greetings, yours,
A. Einstein.
216. To Otto Halpern[1]
[Berlin,] 25 February 1924
Esteemed Colleague,
I found errors in two papers by you that definitely must be corrected, because
they could otherwise cause harm. It would be best if you were willing to send the
notifications yourself. It concerns the following:
1) Ann. d. Phys., IV, 72, 1923, pp.
516–18.[2]
The derivation is incorrect, as well as the
claim.[3]
The error in the cyclic process
lies in that, upon raising the middle mirror not only radiation of the frequency
(ε ∞ small) is emitted out of the interval , but radiation of the fre-
quency also enters into the frequency range (with ε, the action of
the Doppler effect is indicated because of the mobility of the middle mirror, which
although infinitesimally small, is essential to the assessment). The frequency range
in the lower part of the cavity is hence not deprived of radiation, but rather
remains constantly filled with radiation, whereby the consideration becomes
invalid.[4]
2) Zeitschr. f. Physik, 21, 3, 1924, pp.
151–158.[5]
a) Second Bohr objection. Cases may exist where the radiation density influences
the probability coefficients A and
B.[6]
However, this impairs the derivation only
when such influence is systematic and affects A and B in various strengths (multi-
plicatively). This objection is mentioned only by the way, because it does not influ-
ence the cogency seriously anyway. The circumstance that the Stark effect is of
highly differing magnitudes for different lines already shows this. That is why your
objection to the derivation of equation (3) is not tenable,
either.[7]
Experience
ν1 ε – ν2 ν1 –
ν1 ε + ν2 ν1 –
ν2 ν1 –