[Officers of the Navy Forbidden to Give Publicity to Any Hydrographical Knowledge Obtained During Service]
Officers of the Navy, and all other persons in the employment of the Naval branch of the public service, are hereby forbidden to give publicity to any hydrographical knowledge obtained during their service afloat.
Intelligence regarding any contemplated Naval or Military operations; descriptions of Naval vessels or armaments; their destination, or the names of such as are under repair, or fitting for sea, and any other information whatsoever that can be used to the injury of the Government by the public enemy, are also prohibited.
[Secretary of the Navy]
April 22, 1862