Production. Aircraft engines. Foreman F.I. Bowman shows Marietta Morgan how to operate this bomb-test machine used to test reconditioned spark plugs. A young African American girl, Marietta, had formerly been a clerk in a meat market. Her lack of industrial experience, however, has been no handicap for her present war job in a large Midwest airplane plant. She's rapidly becoming a skilled and efficient machine operator. Melrose Park, Buick plant. Sourced from the Library of Congress.