D O C U M E N T 2 5 0 A U G U S T 1 9 2 8 3 9 7 AL [16 296]. Cropped. [1] Horace Clifford Levinson (1895–1968) was an American astrophysicist living in Chicago. He had obtained advanced degrees from both the University of Chicago (1922) and the University of Paris (1923). A copy of the Paris thesis (Levinson 1923) is in Einstein’s reprint collection. See Havas 1993 for further discussion of Levinson’s correspondence with Einstein. [2] Levinson 1924. [3] Levinson considered a system of n bodies and expressed the metric in a power series of their masses in which the functions of the coordinates appear as coefficients. [4] Likely a reference to Einstein 1928b (Doc. 91), presented on 24 November 1927, which contin- ued earlier work contained in Einstein and Grommer 1927 (Vol. 15, Doc. 443). It carries an approxi- mation scheme to obtain equations of motion to the second approximation and mentions at the end that further restrictive conditions might be obtained in the consideration of higher approximations. In his response, Levinson questioned this part of Einstein’s criticism and further elaborated on the rele- vant part of his paper, see his notes in [16 298] and Abs. 653. [5] See, e.g., Einstein 1922c (Vol. 7, Doc. 71), pp. 55–56, to which Levinson referred in his paper, for a discussion of the relevant equations. Levinson 1924, p. 250, defined to stand for the expres- sion , with the energy-momentum tensor, and therefore corresponds to , as defined in eq. (96a) of Einstein 1922c. The equation below then follows in linear approximation with for small under assumption of the coordinate condition . [6] In the equation below, the factor of in the second term of the left-hand side is interlineated with a different pen. should be . The quantities were defined functions of the , see eq. (7) of Levinson 1924. The equation itself follows from the expression for given in eq. (101) on p. 56 of Einstein 1922c (Vol. 7, Doc. 71). [7] In his reply (Abs. 653), Levinson accepted this part of Einstein’s criticism. 250. To Chaim Herman Müntz [Scharbeutz,] 7. VIII. 28. Lieber Herr Münz! Ihre Lösung des Integrationsproblems finde ich sehr interessant sie hat meinen Mut wieder neu belebt.[1] Es wäre sehr lieb von Ihnen, wenn Sie die Lösung des Problems berechneten, welche zu gehört.[2] Ich möchte ferner ein paar allgemeine Bemerkungen anfügen. 1) Die haben bezüglich des Index Vektorcharakter, bezüglich a nicht, da dieser Index sich auf die Lokalaxen bezieht. Ähnlich ist es mit den kleinen die durch A a 1 a n x 1 x 4 F T 1 2 --g T – – T T* g – + = 1 2 – 0 = F A1 a a n 1 2 3 0 = = = 4 j r = h a ha h a a ha + =