corps was further diminished by Osterhaus' DIVISION being withdrawn from Hoveyt's left and sent to guard the crossing of the Big Black by the railroad and Jackson road. This doubled the front covered by Hovey. At the close of the siege the position of the troops investing the city was, from our right, first Sherman's corps, dimished by a DIVISION; SECOND, McPherson]s dimished by a DIVISION; THIRD, McClernand's (now Ord's)corps, also dimished by a DIVISION, fourth, Lauman's DIVISION; FIFTH Herron's DIVISION. The investment was clear only after the arrival of Herron's DIVISION, bring previously weak from the weakness of our force, and was made on the northern instead of the southern side of the city-first, to be near our depot of supplies at Chickasaw Bayon, on the Yazzo River, and to cover that depot; SECONDLY, to be in such a position that a relieving force could not by a rapid movement effect a junction with the garrison of the city before we could attack that force. At the beginning of the siege the enemy's defenses were essentially the same as at its close, making the place and intrenched camp 4 miles long and 2 miles wide, the line of defense not following its windings, being 7 miles long and well adapted to the ground.

DESCRIPTION OF GROUND.

Perphas the best idea of the ground around Vicksburg MAY be obtained by supposing that originally a plateau, having from 200 to 300 feet elevation, here reached the Mississippi, that the fine soil, which when cut vertically, will remain so for years, has gradually been washed away by rains and streams till the plateau has disappeared, leaving in its place an intricate net-work of ravines and ridges, the hatter every where sharp, and the former only having level bottoms when their streams become of some size. It has already been said that the soil when cut vertically will remain so for years. For this reason the sides of the smaller and newer ravines were often so steep that their ascent was difficult to a footman unless he aided himself with his hands. The sides of the ravines were usually wooded, but near the enemy's line the trees had been felled, forming in many places entanglements which under fire were absolutely impassable. At Vicksburg the Mississippi runs nearly south, and the streams which enter it from the east run southwest. One such stream enters the river 5 miles below the city, and the dividing ridge which separates two of its branches was that on which the defensive line east of the city was placed. This line on the northern side of the city was on a diving ridge between two small streams, which enter the Mississippi above Vicksburg.

DESCRIPTION to THE ENEMY'S LINE.

It MAY be said, then, that the enemy's line of defense, leaving the river on the north side of the city where the bluff strikes the river, was generally on a dividing ridge, this bridge being as high or higher than the ground in its vicinity; that in two places the line crossed the valleys of small streams, reaching the river bluff again 2 miles below the city, at a point where the bluff has receded to a distance of 1 mile from the river, and then following the bluff up the river for a mile, to give fire toward the river or any troops that might attempt an attack from the south by moving up between the bluff and the river along the river bottom. This line was well located for seeing the ravine in its