D O C . 3 1 3 C U R R E N T S T AT E O F F I E L D T H E O R Y 4 7 7 Published in Honegger 1929, pp. 126–132. A manuscript [71 721] is also available. [1] Dated by the request to contribute a scientific paper to a Festschrift in honor of A. Stodola’s sev- entieth birthday in Abs. 732. The contributions were due before 15 January 1929. Einstein confirmed his willingness to do so (see Abs. 750) and sent a manuscript before 27 January (see Abs. 864). [2] The paper was requested by Honegger in Abs. 732. [3] At this point in the manuscript, Einstein continued with the following sentence, and then crossed it out: “Für diese Vermessenheit werden wir wie Prometheus an den Felsen geschmiedet und die Gottheit straft uns unentwegt an unserer Leber.” [4] “gewissermassen” was added in the proofs. [5] See Doc. 6 and Einstein 1928e (Doc. 152) for Einstein’s review of Meyerson’s book (Meyerson 1925). The review contains additional details on comparing the Hegelian program with that of rela- tivistic field theory. [6] For details on Weyl’s and Eddington’s approaches toward a unified field theory of gravitation and electromagnetism, and on Einstein’s own work within Eddington’s framework, see Einstein 1925t (Vol. 15, Doc. 17). [7] Einstein refers to Minkowski 1908. [8] For details of Weyl’s geometry and how it incorporates the electromagnetic vector potential, see Vol. 8, Doc. 472, note 3. For the “weakness” of Weyl’s theory mentioned in current document, see Einstein 1918g (Vol. 7, Doc. 8). [9] For a list of all invariants of Weyl geometry, see Weitzenböck 1920. [10] Einstein introduced teleparallel geometry in Einstein 1928n (Doc. 216) for the question of how this new geometry relates to Riemannian geometry and Weyl geometry, see Einstein to Reichenbach, 19 October 1928 (Doc. 292). [11] In the manuscript, the right-hand side of this equation reads:daX2 . [12] Weitzenböck 1928. In correspondence, Einstein first used this notation in Docs. 314 and 316. [13] In the manuscript, the left-hand side of this equation reads: . [14] As in the manuscript, the third term should have a partial derivative in the numerator, and the fourth term should read in the numerator. [15] The bracketed part is missing in the manuscript. The quantity introduced here is the teleparallel connection (see Doc. 216, note 12 for details). [16] The corresponding definition given in Doc. 216, eq. (10) included a factor of 1/2. [17] In the manuscript, this sentence was corrected from an earlier version that read: “Durch Verjün- gung folgen aus diesen Tensoren die Vektoren , von denen zu vermuten ist, dass sie in dieser Theorie die Rolle der elektromagnetischen Potentiale spielen.” [18] For references concerning and discussions of the invariants of teleparallel geometry, see Weitzenböck to Einstein, 1 August 1928 (Doc. 246). [19] Einstein had initially only considered field equations arising from or alone. The combi- nation proposed here was first considered in Doc. 258. [20] Chaim Herman Müntz. The gravitational field of a mass point according to “the original theory of general relativity” is given by the Schwarzschild metric. [21] For a discussion of this point, see Doc. 341. [22] Einstein 1929n (Doc. 365). This last paragraph was added later see Doc. 365, published 30 Jan- uary 1929. daX  a h     = J 1 J 2