The other instance to which I was a witness occurred during the afternoon of the second day's battle, and in the midst of a lull which had followed the retreat of McCook and Crittenden and the falling back of Thomas's right division. The general was sitting in the rear of the line of battle of his right as re-formed, engaged in watching a heavy cloud of dust in the distance, and in such a direction that it might be the enemy, or it might be the reserve forces of Gordon Granger, which had been posted some distance in rear of the battle-field at Rossville, and which it was hoped would march to the aid of the army. The doubt under which he labored cast a visible cloud over the general's spirits, and excited his nerves to an unusual degree. He had no disposition to resume the fight, and, fearful of the result of the next attack of the rebels, was anxious to avoid a resumption of the battle. He consequently watched the development of the cloud of dust in the distance with painful anxiety. If it dissolved to reveal friends, then they were doubly welcome, for fresh friends insured the safe retirement of that fraction of the army which still held its ground. If it disclosed the enemy, then the day and army were lost, and it became the duty of those who formed this "last square" at Chickamauga to throw into the teeth of the victorious enemy a defiance as grandly contemptuous as that of Cambronne, and die. There was no escape if the troops advancing from the rear were, as it was feared, the cavalry of the enemy. General Tom Wood, hearing some one express himself to this effect, threw in a word of encouragement by saying that it was evident it was not cavalry, "for," said he, "don't you see the dust rising above them ascends in thick misty clouds, not in spiral columns, as it would if the force was cavalry," a remark which indicated the close observation of General Wood. The anxiety of General Thomas increased with every moment of delay in the development of the character of the advancing columns. At one time he said nervously to his staff, "Take my glass, some of you whose horse stands steady--tell me what you can see." I was standing near him at the moment looking through a field-glass, and remarked that I felt sure that I could see the United States flag. "Do you think so? do you think so?" asked the general, nervously.