 The Battle of Gettysburg featured the Union Signal Corps in its role of observing the battlefield.The chief signal officer of the Army of the Potomac, Captain Lemuel B. Norton, had field telegraph trains at his disposal, but did not deploy them.On July 1, 1863, a Union signal officer, Lt. Aaron B. Jerome, ascended the cupola of the Lutheran Theological Seminary and the courthouse steeple to observe the enemy's approach and reported to Maj. Gen. Oliver O. Howard.