Press Kit: Discovering the Civil War
Discovering the Civil War
Photographs of the exhibit Discovering the Civil War which opened in the Lawrence F. O’Brien Gallery April 30, 2010 at the National Archives Building in Washington, DC.
All are photos by Earl McDonald for the National Archives.
Cipher disk used to protect Union Army communications. This disc functioned by aligning the letters on the upper two disks with the numbers on the two lower disks. National Archives, Records of the Office of the Chief Signal Officer
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