D O C U M E N T S 4 , 5 J U N E 1 9 2 5 2 9 I hope that my letter finds you in the best of health. I shall be in Arcachon for 4 weeks. Respectfully and sincerely yours, A. Piccard 4. To Auguste Piccard [Berlin,] 9 June 1925 Dear Mr. Piccard, I read your letter of 5 June with the greatest interest upon my return from a trip to South America.[1] I am convinced that through your excellent experiment you have fully decided the issue, within the range of the order of magnitude that I had suspected, and I am very grateful to you for this valuable assistance. Now, as con- cerns the mode of publication, I think that I have no right to figure as a coauthor. It suffices entirely if you say in the publication that I had asked you to conduct an ex- periment that determines, through condensation of ion-free matter, whether this matter is without charge in the electrostatic sense, i.e., whether the order of magni- tude of a possibly anticipated effect corresponds to the dimensional equation[2] . Kind regards, and again, thank you very much P.S. When another idea occurs to me for an experiment of principal importance, I shall certainly knock at your door again with confidence. 5. From Michele Besso Bern, 9 June 1925 Dear Albert, Above all, I would like to thank you for your letter[1] —when would the meeting that will probably bring you here be scheduled?[2] Your conviction that Schouten’s general geometry[3] has no chance of delivering an accurate picture of the overall physical reality—singular points, of course, ex- cluded—is now based on your years of research on the same principles. It would be exceedingly important to fix the trains of thought that led to this negative result—compared to the approaches that seem discouraging because of the vast ε m κ∼