Albert Einstein (1879-1955)
Autograph letter signed ('A. Einstein') to Cornelius Lanczos, n.p., n.d. [1940]
In German. One page, 280 x 216mm. Provenance: Sotheby's, 26 November 1980, lot 171.

A new paper on 'the problem of motion in the general theory of relativity', and another failed attempt on a unified field theory. Einstein is impressed with a theoretical proof Lanczos has sent, though he suggests it might be better to publish it in a journal of mathematics, 'as the actual physics ones have sunk under the pressure of facts to a sort of engineering point of view'. He will encourage the editor of Annals of Mathematics to publish it, as they are about to publish a paper by Einstein and Leopold Infeld 'in which the problem of motion in the general theory of relativity is solely founded on the equations R_ik = 0'. On the other hand, 'all my attempts on a unified theory of gravitation and electricity have miscarried. It appears that we really must move on to fourth order equations, which is quite painful'. The letter concludes with sympathy at the continued uncertainty over Lanczos's academic position.

The paper referred to is presumably A. Einstein and L. Infeld, 'The gravitational equations and the problem of motion, II', Annals of Mathematics 41 (1940), 455–464.