5 3 0 D O C U M E N T 3 3 6 O C T O B E R 1 9 2 4 theory, by twenty equations. If I can determine them by more equations, their sig- nificance will be more definite, as I shall set to them more limits than they actually have. Well I applied this idea to the electron formulae, but did not obtain the result I expected. These considerations led me to the views I have just propounded. —Could you suggest any method to bridge the gap between the implications of the Quantum theory and the actual position of mathematical physics? —I think not yet at present. The differential equations we use have no influence on the matter. I believe a new type of functions will have to be discovered to meet the requirements of the case. But I can suggest nothing at the present stage. After all, we are far from an adequate description of reality. Every day we draw nearer to it but there seems to be a difference of degree between reason and reality. That is probably why I have not yet succeeded in convincing many of my colleagues that the universe is finite though unbound. —I believe you will have a very hard task in this endeavour. Your conclusions, pardon me for saying so, are beyond experimentation. —It might be so, said Einstein with a smile. Yet, if God was to create the Uni- verse according to the new physical theories, I do not see why He could possibly make it infinite. Thomas Greenwood ALS [43 796]. Written on printed letterhead of “Royal Geographical, Society. Kensington Gore. Lon- don, S.W.7.” 95–379. The transcript of an interview was enclosed with the letter. A copy of the pre- sumed transcript, in an unknown hand, is located at the Ottawa Library and Archives Canada, Thomas Greenwood Collection, Series D109, Vol. 7, p. 4. [95 379]. Greenwood (1901–1963). A few weeks earlier, on 12 July 1924, Greenwood had published a report on “Relativity at the International Congress of Philosophy, Naples” and in this report also gave a summary of a paper of his own presented there: “In his paper on ‘The Specification of the Straight Line,’ Dr. T. Greenwood developed the logical arguments which lead him to state in a new way the problem of the characterization of the Euclidean straight line by means of a single axiom which he calls ‘The Postulate of Null-Curvature.’ He establishes this postulate by means of a new hypothetico- deductive system of axioms based on the notions of ‘point’ and ‘distance,’ and uses it to prove the two ordinary postulates of the straight line. This method, which is very simple in itself, has many advan- tages in the logical, the pedagogical, and the scientific field” (Greenwood 1924). During the month of September 1924, Einstein was in Berlin until September 22, when he left for a trip to Vienna, Innsbruck, Zürich, Lucerne, Antwerp, and Leyden, returning to Berlin only ca. October 24 (see Chronology). For the account of their conversation, see the next note. A three-page autograph version of the following interview in an unknown hand is reproduced here under the assumption that it is the original or a copy of the document mentioned in Greenwood’s letter.