...to the various parts of the army up to November 29th, on which day he left Chattanooga again with me for Knoxville. I had been sent to act as chief engineer to the forces detached for the relief of Burnside . Grant had pushed Bragg back from Missionary Ridge towards Resaca and Atlanta, thus separating him hopelessly from Longstreet and rendering effective co-operation between them henceforth impossible...