Complex sentence: The director of the Metallurgical Laboratory, Arthur Compton, supported the idea, and a meeting was arranged with James B. Conant, the President of Harvard University and one of the senior administrators of the Manhattan Project, who was thinking along similar lines.
Split into simpler sentences: The director of the Metallurgical Laboratory, Arthur Compton, supported the idea. He arranged a meeting with James B. Conant, the President of Harvard University and among the senior administrators of the Manhattan Project, who was thinking along similar lines.