Pauli writes about longitudinal photons. The principle of "renormalization" of charge and mass works satisfactorily only in special interactions. Another question: will it be necessary to modify the space-time concept for small dimensions?

Pauli makes further critical remarks about Jordan's cosmology. He writes that some of his assumption should be derived mathematically from a new nuclear theory.

Pauli writes about the date of a conference in Mainz where Pauli intends to lecture on "Die Wissenschaft und das abendländische Denken". He plans to write a paper on "Exclusion principle, Lorentz group and reflexions of space-time and charge".

Pauli writes on the treatment of the eigenvalue problem. The only existing method is the Tamm-Dancoff approximation but Pauli does not believe in it. He will possibly work on the problem with Gürsey. He speaks of a principal difficulty of model which is analogous to that in the "neutrino-theory of light". In the spinor model Pi-mesons and photons are composed of real states and only formally existing mirror states which must be forbidden. There is a discussion of the difficulties resulting from this.

Pauli asks for Källén's opinion about Hurst's paper and quotes Thirring's comment.

Pauli asks about the Copenhagen Conference. He criticises the Heisenberg-Pauli papers, makes remarks on superconductivity and about Dirac's negative mass.

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

Pauli writes about Uhlenbeck's appointment in Utrecht. Pauli is glad that Kronig has written to him, in spite of Pauli's remark regarding the spin problem (in Tübingen). Pauli makes some remarks about him and Uhlenbeck. He thinks that Kronig should go to America, in spite of his doubts. He makes remarks on Jordan's and de Broglie's paper on the neutrino.

Pauli fixes a convenient time for Kronig's visit to Zürich. He writes about a lecture he will give in Turin.