Autograph manuscript signed (at conclusion, 'A. Einstein'), 'Einheitliche Feldtheorie von Gravitation und Elektrizität' [Unified Field Theory of Gravitation and Electricity], [Berlin, before 14 June 1928]

Albert Einstein (1879-1955)
Autograph manuscript signed (at conclusion, 'A. Einstein'), 'Einheitliche Feldtheorie von Gravitation und Elektrizität' [Unified Field Theory of Gravitation and Electricity], [Berlin, before 14 June 1928]
In German. Four pages, 280 x 220mm, with autograph cancellations and emendations, including 17 scientific equations, some editorial markings in pencil, paginated in autograph 1-4, and in red pencil in another hand, 17-20. Leather portfolio, leather-backed box. Provenance: John D. Stanitz (1920-2011) – his sale, Sotheby's New York, 25 April 1984, lot 142 (unsold) – sold after sale to: B. Michael Kiesser (letter to him from Princeton University Library, 4 September 1984) – Sotheby's New York, 14 February 1986, lot 454.

'It is conceivable that this theory will replace the original formulation of the general theory of relativity': Einstein's first attempt to apply distant parallelism to the problem of the unified field theory. In a paper a week previously, Einstein had announced the invention of a new geometric theory based on a Riemannian metric and distant parallelism: here he applies this new theory in an attempt to find a unified field theory of gravitation and electricity.

The introduction of distant parallelism entails that according to this theory, there is something like a straight line, i.e., a line whose elements are all parallel to one another; such a line is naturally not at all identical to a geodesic. Furthermore, in contrast to previous versions of general relativity theory, it contains the concept of relative rest between two point masses (parallelism of two line elements that belong to two different world-lines).

The approach of distant parallelism (Fernparallelismus), announced here, was to be the basis of Einstein's attempts to construct a unified field theory in a number of papers between summer 1928 and spring 1931. News of this new approach prompted widespread popular excitement over the following months, amid a rising belief that Einstein was on the verge of putting in place the third stage of relativity by combining general relativity and Maxwell’s theory of electromagnetism into a single physical and mathematical framework, a 'unified field theory', which would account for all of the then-known fundamental forces of nature. When he published his new field equations in January 1929 the paper was to sell more copies than any other published by the Prussian Academy and was reprinted in translation on the title page of the New York Herald Tribune. Einstein ultimately abandoned the approach after failing to establish a uniquely determined set of field equations.

Einstein was in fact unable to present either this or its preceding paper himself to the Prussian Academy of Sciences, as he was suffering from a serious heart illness after a circulatory collapse in March, and was confined to bed: the paper was therefore presented to the Academy by Max Planck on Einstein's behalf on 14 June 1928. Published as 'Neue Möglichkeit für eine Einheitliche Feldtheorie von Gravitation und Elektrizität' in Preußische Akademie der Wissenschaften (Berlin). Physikalisch-mathematische Klasse. Sitzungsberichte (1928): 224–22. Einstein 1928o. Collected Papers, vol. 16, no. 219.