アーネスト・ローレンス
Smyth possessed security clearances necessary to visit project sites, access documents and to discuss the work with the research personnel. Groves approved Smyth's request to hire another Princeton physicist, Lincoln G. Smith, as a research assistant. A letter to the Manhattan Project's senior managers, Kenneth Nichols, Robert Oppenheimer, Ernest Lawrence, Harold Urey, and Franklin Matthias, explained: