<Statements of Rear Admiral Thomas Washington, Chief Bureau of Navigations; Capt. William D. Leahy, Director Gunnery and Engineering Exercises, Office of Naval Operations; Rear Admiral John A. Hoogewerff, Superintendent Naval Observatory; and Capt. William C. Asserson, of the Hydrographic Office> [microform] : hearings before the United States House Committee on Naval Affairs, Sixty-Sixth Congress, second session, on Jan. 23, 1920