Southern Historical Society Papers, Volume 16.
Reverend J. William Jones, Ed.

To decipher the message, the key was written over it, and the process by which it was put into cipher reversed. To facilitate reading the cipher messages, Captain Wm. N. Barker, of the Signal Corps, invented a simple but convenient apparatus. The alphabetical square was pasted on a cylinder and revolved under a bar, on which was a sliding pointer. Under the pointer and along the bar was pasted the alphabet in a horizontal line. The pointer was brought to the letter in the key on the bar, and the letter in the word to be converted was rolled up under the bar and the pointer rested on the required substitute letter. A model of the Confederate apparatus is preserved among the Confederate records in the War Department at Washington.

The Confederate authorities were sometimes so careless or unskillful in ‘putting up’ their cipher dispatches that some important ones, which fell into the hands of the enemy, were deciphered without much trouble. One from General Beauregard, just after the battle at Shiloh Chapel, giving the number and condition of his forces at Corinth, was put up by merely putting the last half of the alphabet first; that is, substituting ‘M’ for ‘A,’ ‘N’ for ‘B,’ ‘O’ for ‘C,’ etc. This dispatch fell into the hands of the enemy, and first reached Richmond in a ‘Yankee’ newspaper translated.

A message from Mr. Davis, at Montgomery, to General E. Kirby Smith, commanding the Trans-Mississippi Department, was partly in plain language and partly in cipher, in which is found the following: ‘By which you may effect o—t p g g e x y k—above that part —h j o p g k w m c t patrolled by the,’ etc., etc.

An expert of the United States Military Telegraph Corps guessed that that part of the dispatch was meant to read: ‘By which you may effect a crossing above that part of the river patrolled by the,’ etc., etc. The guess was right, and by applying it, the key-phrase was discovered to be ‘complete victory,’ and there was, of course, no trouble in reading what remained of the message in cipher. The author of the history of The Military Telegraph in the Civil War says this meaning occurred to him at first sight, and would have occurred to any one familiar with military affairs in that section.

The same writer makes the reflection: ‘It is a question if the Confederate cipher system was any more difficult to the uninitiated than one of the first examples of secret writing found in history. We ’