Beardslee telegraph

The electric telegraph had come on the scene in the 1840s and was gradually being adopted for both civilian and military uses. In the U.S. Army during the Civil War, however, the electric telegraph was by and large kept out of the hands of military commanders in the field and served instead as a rather private tool for Secretary of War Edwin Stanton and his personal staff--much to the consternation of Chief Signal Officer Myer.

The Signal Corps made do with the less powerful Beardslee telegraph, a magneto-electrical device (pictured here). Writes Raines, describing the battle of Chancellorsville: "The Beardslee's revolving magnets could not generate enough electricity to transmit signals more than about five to eight miles. Therefore, it alone could not connect the new commander of the Army of the Potomac, Maj. Gen. Joseph Hooker, situated on the south side of the Rappahannock, with his chief of staff, General Butterfield, at general headquarters over ten miles away on the other side of the river. Using both electrical and visual signals, the Signal Corps took three hours to deliver messages between them...

"The system broke down completely when Hooker and Butterfield overloaded it, sending more messages than the officers and equipment could handle...[T]he inadequacy of the Union's field communications contributed to the failure of the Chancellorsville campaign."