D O C U M E N T S 5 1 9 , 5 2 0 M AY 1 9 2 9 4 4 5 519. To Herbert C. Hoover[1] Berlin, 6 May 1929 Dear Mr. President, I have read the telegram with which you have honored me, and was deeply ashamed and delighted at the same time. Ashamed, because no one, least of all I, merits such an honor delighted, because this is a testimony to the high regard in which the powerful of this world hold intellectual values in our time. I know that I am only one of many who are so fortunate as to be able to use their strength in the service of the understanding of that which exists. The demonstration of your rec- ognition and sympathy may hold for all, since one person is no more than a speck of dust in the development of the human spirit. With my greatest respect and deeply felt gratitude, your A. Einstein 520. From Élie Cartan[1] Le Chesnay (S. et O.) 27 avenue de Montespan, 8 May 1929 Dear, esteemed Sir, I ask your pardon for taking some moments of your time, which is so valuable for science I decided to write to you on the advice of my friend Langevin.[2] In your recent notes in the Sitzungsberichte concerning a new general theory of relativity, you introduced into a Riemannian space the notion of “distant parallelism.”[3] Now, the notion of a Riemannian space with the attribute of distant parallelism is a particular case of a more general idea, that of a space with a Euclid- ean connection, which I introduced in compact form in 1922 in a note in the Comptes rendus (vol. 174, pp. 593–595),[4] which appeared just at the time when your were giving your lectures at the Collège de France [5] I even recall trying to show you the most simple example of a Riemannian space with distant parallelism