Before departing for the United States on 7 January 1939 with his son Erik to attend the Fifth Washington Conference on Theoretical Physics, Bohr promised Frisch that he would not mention fission until the papers appeared in print, but during the Atlantic crossing on the SS Drottningholm, Bohr discussed the mechanism of fission with Leon Rosenfeld, and failed to inform him that the information was confidential. On arrival in New York City on 16 January, they were met by Fermi and his wife Laura Capon, and by John Wheeler, who had been a fellow at Bohr's institute in 1934–1935. As it happened, there was a meeting of Princeton University 's Physics Journal Club that evening, and when Wheeler asked Rosenfeld if he had any news to report, Rosenfeld told them. An embarrassed Bohr fired off a note to Nature defending Meitner and Frisch's claim to the priority of the discovery. Hahn was annoyed that while Bohr mentioned his and Strassmann's work in the note, he cited only Meitner and Frisch.