Pauli asks about the possibility of visiting Copenhagen during his vacation. He says that he met Heisenberg in Copenhagen. He talks about his own work on heat conduction in solids.

Pauli talks about Bohr's paper on the statistical interpretation of quantum results which has its origin in the decision between observed object and measuring instrument. Critical remarks are made on the paper, but Pauli is still very positive about Bohr's conception, especially his view that the stationary states are as real as the particles themselves.

Pauli sends Bohr a short summary of his calculations on the H-atom using the "Göttinger" quantum mechanics. He writes about the difficulty of the excluded pendulum orbits (R=0), about the great progress made by Heisenberg on quantum mechanics and on Heisenberg's theory which may actually not not suffice to explain the two-term system of He. He also talks about other problems that are still open, like the time-dependent processes.

Pauli is glad about the changes Bohr made in his manuscript, in particular about his explanation of complementarity. He looks forward to meeting him in Hamburg.

Pauli asks if the last proofs of Bohr's paper are completed; if so, he would like to come to Copenhagen for some talks.

Jordan replies to Pauli's letter of the 17 July 1953. He gives certain results of the calculations of Schücking, which are based on Jordan's cosmological equation.