If any additional testimony is needed as to the masterful part played by Smith at Chattanooga, it is found in the fact that Grant made haste to attach him to his own staff and to recommend him for promotion to the grade of major-general to take rank from the date of his original appointment, declaring in support of his recommendation that he felt "under more than ordinary obligations for the masterly manner in which he discharged the duties of his position." Later he recommended that Smith be put first of all the army on the list for promotion, adding: "He is possessed of one of the clearest military heads in the army, is very practical and industrious," and emphasized it all with the highly eulogistic declaration that "no man in the army is better qualified than he for the largest military commands." It is noteworthy that about the same time General Butler with whom he had served for a short season, made an application to have General Smith re-assigned to his command, but the Secretary of War, having evidently forgotten his order for Smith's arrest at the close of the Gettysburg campaign, wrote: "The services of William F. Smith, now Chief Engineer in the Army of the Cumberland, are indispensable in that command, and it will be impossible to assign him to your Department." But this was not all. General George H. Thomas, the soul of honor and fair dealing on the 20th of November, 1863, although General Smith had already been transferred from his own to the staff of General Grant, formally recommended him for promotion in the following striking and comprehensive words: "For industry and energy displayed by him from the time of his reporting for duty at these headquarters, in organizing the Engineer Department, and for his skillful execution of the movements at Brown's Ferry, Tennessee, on the night of October 26th, 1863, in surprising the enemy and throwing a pontoon bridge across the Tennessee River at that point, a vitally important service necessary to the opening of communications between Bridgeport and Chattanooga." Certainly no language could be more clear and unequivocal than this, and yet, as though General Thomas wished to remove all chance of doubt as to whom the highest credit was due, he declared in a later and more formal official report: "To Brigadier General William F. Smith, Chief Engineer, should be accorded great praise for the ingenuity which conceived and the ability which executed the movements at Brown's Ferry."