The President of the United States of America, authorized by Act of Congress July 9, 1918, takes pleasure in presenting the Army Distinguished Service Medal to Lieutenant Colonel (Air Service) Elbert J. Hall, United States Army Air Service, for exceptionally meritorious and distinguished services to the Government of the United States, in a duty of great responsibility during World War I, in the designing of the Liberty engine and subsequently in the adapting of the Le Rhone engine to the American methods of production and also in pushing to completion the American adaptation of the De Haviland plane.