Autograph letter signed ("A. E.").
4to. 2 pp. on 2 single leaves.
In German, to his assistant, the mathematician Ernst Gabor Straus, proposing a solution of equations connected to a unified field theory: "Now I have a very convenient method for the solution of our equations. It isn't the most general solution but you can already tell that it contains the simplest. I calculate in A (and not B) using the equations that you recently wrote down for me [..]". These general remarks are followed by four sets of equations and comments. Einstein concludes: "From II results Ax and, if we're lucky, it also corresponds with Ib. If not, the specialization was too violent for A not to have two extreme indices occur. Generally, the calculation won't be without errors. But I do believe that we will reach our goal comfortably following this path [...]".
Ernst Gabor Straus (1922-83) was Einstein's assistant at the Institute for Advanced Study in Princeton from 1944 to 1948. Together they worked on a unified field theory and published three papers on the ultimately unfinished theory. In 1950 Straus graduated from Columbia University with a doctoral thesis entitled "Some Results in Einstein's Unified Field Theory".
With some calculations and equations by Straus in pencil (verso). Well preserved.