Details

EINSTEIN, Albert (1879-1955). Autograph letter signed ('A. Einstein') to Hermann Müntz, n.p. [postmarked Potsdam], 20 November 1929.

In German, 1½ pages, 276 x 219mm. Envelope.

The search for a unified field theory – one which could account for all of the fundamental forces in nature – was the abiding preoccupation of Einstein's last decades. His 1929 equations constituted his first major attempt. His lecture in Paris (on 8 November) was published in the

In German, 1½ pages, 276 x 219mm. Envelope.

**Unified Field Theory.**Einstein explains the framework of his earliest major attempt at the unified field theory: 'The theory makes me very happy, and my belief in it is constantly increasing. I have recently lectured on it in Paris'. He sets out in turn the equations and their corresponding identities, one of them marked as 'Vertauschungsrelation' (transposition relationship), and then a process by which the orders of magnitude can be made to disappear: 'This is the strong indication of the compatibility of the equations'. As a postscript on the verso, Einstein explains how in the first approximation his equations permit in a remarkable way a choice of coordinates according to specified conditions through which a decay of the equations can be achieved – he sets this out in both the Newtonian and the Maxwellian form.The search for a unified field theory – one which could account for all of the fundamental forces in nature – was the abiding preoccupation of Einstein's last decades. His 1929 equations constituted his first major attempt. His lecture in Paris (on 8 November) was published in the

*Annales de l'Institut H. Poincar**é*(1930), under the title 'Théorie unitaire du champ physique'. Hermann Müntz was a Polish-German mathematician, author of the Müntz approximation theorem. He collaborated closely with Einstein in the years following 1927, and his help is acknowledged in a number of papers.## Brought to you by

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