This letter is a reply to Bohr's letter of the 15th July. Pauli writes about Jordan's manuscript. He criticises its last paragraph where Jordan does not distinguish between the particles (de Broglie field) and the electromagnetic field. He talks about Jordan's and his own work on radiation electrodynamics in the absence of charged particles. He also writes about a paper by de Broglie in the Journ. de Phys. which attempts to harmonize between dualism of waves and corpuscles on the one hand and complete determinism of physical events on the other hand.

Pauli asks if Kronig would be ready to be his assistant in Zürich. He writes about the conditions and colleagues there.

Pauli says that he will write to Kronig next year.

Pauli comments on a paper by Weyl published in Z. Phys. about quantum physics and group theory.

Pauli urges Kronig to come to Zurich for the summer term. Addendum for Kramers about Pauli's paper with Jordan.

Heisenberg writes about his work on ferromagnetism. There are three approximations: 1)free electrons with Fermi-statistics, 2)Bloch's approximation of lattice potentials, 3)Heitler-London approximation of exchange of valency electrons of two atoms in the third approximation.

Heisenberg writes about Pauli's remarks on the H theorem in the case of the interaction of several oscillators and the connection with Dirac's theory.

Pauli talks about a paper by Holtsmark in Naturwissenschaften.

Pauli would welcome a new assistant. He makes some remarks on breit, Bloch and his physics.