Two Notes On the Probability of Radiative Transitions

In 1 we compute the rate at which electrons and protons should, on Dirac's theory of electrons and protons, annihilate each other; this gives a mean life time for matter of the order of 10^-10 sec.In 2 we compute by Dirac's radiation theory the relative probability of radiative and radiationless transitions; we obtain an expression substantially equivalent to that derived by Heisenberg and Pauli.