Pauli writes more about hermitic operators.

Pauli writes about the impossibility of half-integer spin in a theory with a four-vector Psi which is quantized according to Fermi statistics. He writes also of the five-dimensional theory and its prospects.

Pauli writes more about his plans for his visit to Sweden.

Pauli reports in detail on Pais' lecture in Holland on "isotopic spin and mass quantization" and on his introduction of the "W-space". Pauli writes about Jordan's cosmological equations. Pauli thinks that Einstein's model is simpler and more convincing. He does not see the advantage of the introduction of a changing gravitational constant. The appendix contains ideas about the statistical theory of heat.

Pauli requests reprints of Wergeland's latest work for a letter of recommendation.

Pauli writes of his doubts concerning commutators in Klein's Bohr-Festschrift article.

Pauli makes comments on the second draft of Klein's article.

Pauli discusses matrix representation of Maxwell's equations, relation of Heisenberg-Pauli to Dirac theory, problem of self energy. He opposes Dirac's interpretation of negative states and Bohr's views on continuous beta spectrum.

Pauli awaits experiments on beta-decay "neutron" hypothesis. Pauli asks for an answer from Bohr to Pauli's arguments against failure of energy conservation in his letter of 12 Dec.

Pauli makes a comparison of Klein's theory with his relevant lecture given in Paris.