Cipher No 9, Union Telegraphic Cipher Book, c. 1861-1862, used by U.S Civil War General Joseph Hooker at the battle of Chancellorsville, Virginia, to secure messages sent by telegraph. Exhibit in the National Cryptologic Museum, Fort Meade, Maryland, USA. All items in this museum are unclassified; items created by the United States Government are not subject to copyright restrictions.
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