D O C U M E N T 4 1 7 O N G E N E R A L R E L A T I V I T Y 6 6 7 und (14) eine Beziehung zwischen der Stromdichte, dem metrischen und dem Gra- vitationsfelde. Man erhält nach einfacher Umformung[22] . (16) Ausserhalb der elektrischen Massen ( ) gelten aber wieder die Gleichungen (3) der Riemannschen Geometrie. Innerhalb der elektrischen Massen aber ver- schwindet die allgemeine kovariante Ableitung des metrischen Tensors nicht. Hier erst unterscheidet sich diese Theorie von der des selbständigen elektromagneti- schen Feldes. Höchst interessant ist es, dass nach der hier entwickelten Theorie die beiden Vorzeichen der Elektrizität nicht gleichwertig auftreten.[23] Der Grund liegt in der durch Gleichung (7)[24] gegebenen Verknüpfung von Gravitationsfeld und elektro- magnetischem Feld. Ob die beiden Invarianten I1 und I2 zur Darstellung des Elek- trons ausreichen, wird man erst nach Ausrechnung des zentralsymmetrischen statischen Problems entscheiden können [25] die interessante Frage ist die, ob es solche singularitätsfreie Lösungen beider elektrischer Vorzeichen gibt. Singapore. Januar 1923.[26] AD. Mastrobisi 2002, pp. 287–297. [2 092]. The manuscript consists of nine pages. Page numbers that appear in the original in the top right corner of each page are here placed in the margin in square brackets. Pages [1– 4] were written on the back of pp. [4, 3, 2, and 8], respectively, of a manuscript on the theory of relativity written in English by an unknown hand [2 095] pages [5–9] were written on the back of stationery “Nippon Yusen Kaisha S. S. ‘Haruna Maru.’” [1]This document is dated on the assumption that it is the manuscript that Einstein mentions in his diary, in the entry of 9 January 1923 of Doc. 379. [2]Christoffel 1869 for a historical discussion, see Reich 1994, pp. 62–62, 226–228. [3]On the history of the concept of a linear connection and its geometrical interpretation, see Reich 1992, 1994, and Stachel 2007 see also Einstein 1923e (Doc. 425), note 1. [4]Asymmetric, linear affine connections are associated with the geometrical concept of torsion, which was introduced in a brief note by Cartan just prior to Einstein’s visit in Paris (see Cartan 1922b). It was presented at the Académie des Sciences on 27 February 1922 for submission in its pro- ceedings. Six years later, when Einstein published his theory of distant parallelism, Cartan reminded him of his earlier work on generalized connections and mentioned, in particular, a conversation about this topic that the two of them had during a meeting at Hadamard’s home in 1922. For details see Sauer 2006, p. 421 see also the slightly more explicit argument for taking the connection to be sym- metric in the published version, Einstein 1923e (Doc. 425), p. 34, and similar arguments in Weyl 1919b, p. 101, and Pauli 1921, p. 586. Explicit considerations of asymmetric connections are also found in Doc. 418, pp. [47], [49]. [5]Compare Doc. 418, pp. [50]–[49v]. [6]The modern literature speaks of this condition as the condition of compatibility between metric and connection see, e.g., Goenner 2004, especially p. 20. For the notation, see also note 19 below. [7]See Einstein 1923e (Doc. 425) and its note 3. [8]Einstein had favored such a conformal approach himself for a while, without taking on board Weyl’s link to the electromagnetic field. Einstein’s own conformal approach (see Einstein 1921e [Vol. 7, Doc. 54]) can thus be seen as an intermediate step between Weyl and Eddington as they are presented here. [9]Eddington 1921a and 1923, chap. 7, sec. 2. gαβ μ 6 7 --( - δμ αiβ δμ βiα) + 4 7 --gαβiμ - – = [p. 9] iα 0=