The most remarkable of Geary's exploits was the famous "midnight battle of Wauhatchie," a sort of companion picture to Joe Hooker's "battle above the clouds." It took place, too, at the foot of the mountain on which Hooker fought, and was, in a measure, preliminary to that struggle. It was fought for position, but a position of vital importance to both the rebels and Union forces, and consequently it was fought for with great desperation. The movement which brought it about was the first of those looking to the relief of the starving army at Chattanooga, and the purpose was to occupy a position which would cover a road by which provisions could be brought from the railroad terminus at Bridgeport. The occupation of this position was absolutely necessary, and Geary was fully impressed with the importance of quickly seizing and desperately holding on to it. By the success of the movement the route to Bridgeport would be shortened by many miles; on its being thus shortened depended the provisioning of Chattanooga; on this contingency depended the holding of that position, and on the retention of that position the safety of the army and its immense and valuable material. Geary seized the position with great alacrity, and much to the astonishment of the rebel Longstreet, who watched him from the summit of Lookout Mountain. From his position on "Signal Rock"--an overarching rock on the western side of the mountain--Longstreet had before his eyes the whole country as on a map, and when, in the dusk of evening, the camp-fires of Geary and Howard's troops located the positions which Hooker had seized and was fortifying, the importance of the success attained flashed upon Longstreet's mind in an instant, and he saw, in the seizure of Wauhatchie by Geary, the virtual relief of the besieged garrison of Chattanooga. He at once communicated with Bragg, and on explaining the altered situation to that officer, the latter at once directed Longstreet to attack Geary and Howard, and drive them back at all hazards. Longstreet returned to his position on "Signal Rock," and soon had his troops in readiness to descend from their position on the mountain, and assault Geary at Wauhatchie. From his position on "Signal Rock" Longstreet directed the assault by signals, and to this circumstance, singularly enough, he owed his defeat. Geary's force was totally inadequate to contend with the superior forces of the enemy. General Schurz, who was sent by Hooker to re-enforce him, never reached the position, and but from the fact that Geary's signal-officers could read the rebel signals, he must have been overwhelmed and driven from the position. For some months previous to this battle our signal-officers had been in possession of the rebel signal code, and hence the flaming torches of Longstreet's signal-officers on "Signal Rock" revealed to Geary every order given to the rebel troops advancing against him. He was thus made aware of Longstreet's plan of attack,