Pauli expresses his doubts about the validity of his exclusion-principle in more complicated cases. He wants to discuss it in Tübingen on Jan. 9 1925.

Pauli anounces his arrival in Tübingen on 9 Jan. 1925.

Pauli asks about stopping off at the Frankfurt institutes on his return trip from Göttingen.

In this reply to a letter from Pauli, Bohr develops his exclusion principle and attempts to explain this rule in the framework of the electronic orbit model.

Pauli talks about a formula made by Kramers and about his doubts about Goudsmith's idea on the spin of the electron.