Ehrenfest is looking forward to see Pauli in Leiden. he mentions some papers by Heisenberg, Hund and on group theory, on which he wants to ask Pauli several questions.

Ehrenfest gives some personnal remarks on Oppenheimer and sends him to pauli. He also makes a comment on rutgers.

Ehrenfest discusses the disappearance of the "zeroth-order spectrum" for X-ray diffraction in liquids (Zernike-Prins, in: Z. Phys. : 41 (1972), pp.190). He asks Pauli to calculate it.

Ehrenfest discusses in a joking language the results of some of his investigations in the light of Pauli's exclusion principle.