Pauli congratulates Heisenberg on the birth of his child. He makes a remark on the cut-off frequency of long waves and about Yukawa's theory of nuclear forces.

Heisenberg objections about the impossibility of the localization of particles in the nucleus with a precision greater than h/($\mu$.c). He does not believe in a theory where $\mu$<M can be assumed. The theory of $\gamma$-ray interferences is a good example of the applicability of the explosion-hypothesis. He speaks of his belief in the existence of definite rest-masses of the same order of magnitude (h.c)/$\mu_{o}$.

Pauli talks more about cosmic rays and the occurence of light particles (electrons) in showers.

Pauli reports on his activities in Zürich and on his travel to England and Holland.

Heisenberg talks about the political restrictions on contributors to the Sommerfeld issue of the "Annalen der Physick" and about his paper with Euler on cosmic radiation. The result refutes the theory of Uhlenbeck-Konopinski.

Pauli writes about Kahn's paper. He hopes that Kahn will come to Zürich. He writes about a reply to Stark's attacks on "dogmatic" physicists.

Pauli reacts sharply on "non-scientific secondary conditions" of certain publishers as regards the racial origin of scientific authors. He talks further about cosmic ray experiments and their interpretation.

Pauli writes about a paper he is writing for the Sommerfield issue of Physics Reviews.

Pauli asks Einstein to help F Kottler who, as a jew, had to leave Austria and is looking for a job abroad. He also makes some remarks on Einstein's paper on a closed five-dimensional continuum. He also hopes that Bargmann will be of some help to Einstein.

The letter gives a short evaluation of the political situation, in connection with Kemmer's doubts about England. He replies to some physics points raised by Kemmer.