Cumberland, the object being to thrust our forces through our lines, and effect a lodgment on the railroad between Atlanta and East Point. The attack, however, wa not made.

August 5, the Chattahoochee river railroad bridge was completed,and our trains ran up to three-mile post. By General Sherman's direction, I sent Lieutenant Ernst to Marietta to superintend the construction of defenses at that place. An attack was ordered for 2 p. m., the object being as given above, but again no attack was made.

August 6, the attack, twice before ordered, was made, but repulsed. The two corps of the Army of the Cumberland, forming the left of our army, kept steadily pushing forward, but without anything like siege approaches. Our sharpshooters had gained such positions as rendered it difficult for the enemy to work his guns.

August 7, the attack made yesterday was renewed, and proved successful. It was found that the line of rifle trenches carried by the assault was not the enemy's main line, but stood nearly perpendicularly to it. The Army of the Tennessee moved forward about 400 yards, swinging upon the center of its right wing as a pivot. The successive advances, either directly or by swing upon some part of the line as a pivot, were made in the following manner - by pushing forward, just before daylight, a strong line of skirmishers to the position chosen beforehand, which maintained its ground during the day, each man getting such cover as he could, generally by scooping out a rifle-pit at the foot of a tree, behind a log or stone, in which they could find shelter. As soon as night made it possible, working parties were thrown out to the skirmish line and connected by the ordinary rifle trenches the entire chain of rifle-pits. These lines were continually being strengthened until it was desired to make another advance, when the operation was repeated. In this way our lines were pushed at any point we wished to within 200 yards of the enemy's and with slight loss. I wish here to impress upon the Engineer Department the fact that nothing like regular siege approaches were attempted. I frequently informed the general commanding that we could easily, at any time, push forward saps and pierce the enemy's lines, yet when we had done so we would have accomplished very little, since the enemy would take the precaution to construct another a few yards in his rear. The general understanding this perfectly always told me that he did not wish anything of the kind done, that he intended to gain possession of Atlanta by operating upon the enemy's lines of communication, until he either brought on a general engagement, in which event he expected to gain a decisive victory, or compel the enemy to evacuate the city, which he could easily do, as the place was not, and it was evident that it could not be, completely invested.

August 8 and 9, was at work everywhere strengthening our lines. Commenced the construction of batteries for 4 1/2-inch huns which had been ordered. These were placed in position as follows: Two in front of the Twentieth Army Corps, near the Chattanooga railroad, and two others in front of the Sixteenth Corps. The whole of the Army of the Tennessee advanced about three-eighths of a mile in the manner already described, and the line of the Army of the Cumberland were straightened, so the whole line was as far advanced as the salients had been. The Army of the Ohio was engaged in intrenching itself in its position south of Utoy Creek.

August 10, 11, and 12, no advanced were made.