Farrell was briefed on the physics of the atomic bomb by Robert Oppenheimer , and he made several extended tours of the Alamogordo Bombing and Gunnery Range , which had been chosen as the site for the Trinity test . On signing a receipt for the plutonium from Oak Ridge , Farrell commented : Farrell observed the Trinity ( nuclear test ) with Oppenheimer from the control dugout located from the test tower . In his report on the test to President Truman on 21 July 1945 , Farrell stated :
Trinity ( nuclear test )
Trinity (nuclear test)
Thomas Farrell (general)