EINSTEIN, Albert. Autograph manuscript, comprising calculations and arguments from the paper 'Einheitliche Theorie von Gravitation und Elektrizität' [Unified Theory of Gravitation and Electricity], n.p., n.d. , comprising the conclusion of section 7 of the paper, from the paragraph after equation 53 to the end, a few cancellations and emendations, one printer's marking, one page (numbered 19), 4° (282 x 222mm), (slight wear to edges).
The manuscript is from a paper written in collaboration with Walther Mayer, which Einstein submitted to the Prussian Academy of Science at its session on 22 October 1931, published in Sonderausgabe aus den Sitzungberichten der Preussischen Akademie der Wissenschaften, Physikalische-Mathematische Klasse, 1931, XXV (this page corresponds to pp.555-6 of the printed text).
The Unified Field Theory, probably Einstein's most visionary project, was intended to solve one of the outstanding problems of fundamental theoretical physics, that of how to fit gravity into a quantum field theory. Einstein spent the latter part of his life trying to bring together the general theory of relativity, which was concerned with gravity, and James Clerk Maxwell's theory of electro-magnetism. All his attempts, produced, as he wrote to a friend, 'in any agony of mathematical torment', were abandoned, and the problem has continued to defy solution.
Einstein's first outline of a unified field theory was published by the Prussian Academy of Sciences in 1928. In January 1929 he submitted a new paper for examination. From the end of 1929 he worked in collaboration with his Austrian assistant, Walther Mayer (1887-1949), on a unified theory of gravity and electricity. Mayer accompanied Einstein to America from December 1930 to March 1931. Sailing from Southampton on the Belgeland, they worked throughout the voyage in three flower-filled staterooms, permanently guarded from intrusion (R.W. Clark, Einstein, 1978, p.402). Their first joint paper was submitted to the Academy on 23 April 1931. The present manuscript represents part of another attempt, in which they use the ideas, published in 1921, of Theodore Kaluza, who had introduced a five-dimensional space-time in order to unify gravitation and electro-magnetism.