Pauli letter collection: letter to Wolfgang Pauli

Heisenberg replies to Pauli's letter. He does not fully agree with Pauli that the inertia of self-energy of the spin is of the order (M.c)/h, because the absorptions of mesons indicate a much smaller cross-section for scattering by protons such as that of Bhabha-Heitler, and because the additional inertia does not change the nuclear forces. The spin-inertia plays a role only in the case of rapidly changing fields. He agrees with Pauli's remark on electron spin.