Settlement of Weisskopf's travel expenses.

Pauli refers Klein to Belinfante (Physica) for side conditions needed for Klein's equations. Pauli describes the conditions.

Pauli writes on the unitary representations of the Lorentz group and on the meson theory.

Pauli discusses the treatment of interaction between heavy particles and electrons. He comments on Marshak and Weisskopf'calculations. The main problem is now the creation of mesons in explosions.

Pauli thinks that classical field theories cannot contribute to a real solution of the problems which Landé has dealt with.

Pauli writes about the work done in Berkeley on meson theory. He writes about his lecture on Cosmic rays theory. He writes about Rooseland's report on the Nazi terror in Norway.

Pauli writes the first letter of welcome for Jauch's arrival in the U.S.A. He comments on the "cut-off" technique in theoretical physics.

Pauli comments on the meson theory with integer spin and strong coupling. He writes about Schwinger's approach to the problem. He writes about nuclear forces and about the competition between the nucleon's interaction energy and the energy of isobars. He writes about pair theory. He comments on a correspondence with Dirac about the elimination of divergences in quantum electrodynamics.

Pauli makes further remarks on Dirac's theory. He withdraws the objection concerning singular processes. He considers ways to derive Einstein's radiation laws. He makes some calculations on low-frequency photons. He comments on higher order corrections of the Klein-Nishina formula. He nnounces the publication of a paper about Dirac's theory.

Pauli sends a letter of congratulation on Born's 60th birthday. He makes some remarks on quantized field theory and on meson theory in particular. He adds some personal remarks on colleagues in Switzerland, Germany and the U.S.A.