D O C . 5 3 C A L C U L A T I O N S 9 1 ADX. [69 228, 73 983]. At the bottom right corner, the words “Einstein Etwa 1925” are written in what appears to be Paul Ehrenfest’s hand. Ehrenfest’s notes on the verso of the document are omitted. [1]Dated on the assumption that it was written at about the same time as Einstein 1923n (Doc. 52). [2]Eqs. (1) correspond to eqs. (1) and (2) of Doc. 52. [3]This equation corresponds to eqs. (3) and (3a) of Doc. 52. [4]Eq. (2) corresponds to eq. (8) of Doc. 52. The term that is only indicated by a dot would be . [5]Eq. (3) corresponds to eq. (9) of Doc. 52. [6]This equation corresponds to eq. (10a) of Doc. 52. In the publication, the Hamiltonian has an additional term and a factor β. 1 6 --iνδμ - σ 2α –g