After the unsuccessful assault of the 22d the work of the regular siege began. Sherman occupied the right starting from the river above Vicksburg, McPherson the centre (McArthur's division now with him) and McClernand the left, holding the road south to Warrenton. Lauman's division arrived at this time and was placed on the extreme left of the line.
In the interval between the assaults of the 19th and 22d, roads had been completed from the Yazoo River and Chickasaw Bayou, around the rear of the army, to enable us to bring up supplies of food and ammunition; ground had been selected and cleared on which the troops were to be encamped, and tents and cooking utensils were brought up. The troops had been without these from the time of crossing the Mississippi up to this time. All was now ready for the pick and spade. Prentiss and Hurlbut were ordered to send forward every man that could be spared. Cavalry especially was wanted to watch the fords along the Big Black, and to observe Johnston. I knew that Johnston was receiving reinforcements from Bragg, who was confronting Rosecrans in Tennessee. Vicksburg was so important to the enemy that I believed he would make the most strenuous efforts to raise the siege, even at the risk of losing ground elsewhere.
My line was more than fifteen miles long, extending from Haines' Bluff to Vicksburg, thence to Warrenton. The line of the enemy was about seven. In addition to this, having an enemy at Canton and Jackson, in our rear, who was being constantly reinforced, we required a second line of defence facing the other way. I had not troops enough under my command to man these. General Halleck appreciated the situation and, without being asked, forwarded reinforcements with all possible dispatch.
The ground about Vicksburg is admirable for defence. On the north it is about two hundred feet above the Mississippi River at the highest point and very much cut up by the washing rains; the ravines were grown up with cane and underbrush, while the sides and tops were covered with a dense forest. Farther south the ground flattens out somewhat, and was in cultivation. But here, too, it was cut up by ravines and small streams. The enemy's line of defence followed the crest of a ridge from the river north of the city eastward, then southerly around to the Jackson road, full three miles back of the city; thence in a southwesterly direction to the river. Deep ravines of the description given lay in front of these defences. As there is a succession of gullies, cut out by rains along the side of the ridge, the line was necessarily very irregular. To follow each of these spurs with intrenchments, so as to command the slopes on either side, would have lengthened their line very much. Generally therefore, or in many places, their line would run from near the head of one gully nearly straight to the head of another, and an outer work triangular in shape, generally open in the rear, was thrown up on the point; with a few men in this outer work they commanded the approaches to the main line completely.
The work to be done, to make our position as strong against the enemy as his was against us, was very great. The problem was also complicated by our wanting our line as near that of the enemy as possible. We had but four engineer officers with us. Captain Prime, of the Engineer Corps, was the chief, and the work at the beginning was mainly directed by him. His health soon gave out, when he was succeeded by Captain Comstock, also of the Engineer Corps. To provide assistants on such a long line I directed that all officers who had graduated at West Point, where they had necessarily to study military engineering, should in addition to their other duties assist in the work.
The chief quartermaster and the chief commissary were graduates. The chief commissary, now the Commissary-General of the Army, begged off, however, saying that there was nothing in engineering that he was good for unless he would do for a sap-roller. As soldiers require rations while working in the ditches as well as when marching and fighting, and as we would be sure to lose him if he was used as a sap-roller, I let him off. The general is a large man; weighs two hundred and twenty pounds, and is not tall.
We had no siege guns except six thirty-two pounders, and there were none at the West to draw from. Admiral Porter, however, supplied us with a battery of navy-guns of large calibre, and with these, and the field artillery used in the campaign, the siege began. The first thing to do was to get the artillery in batteries where they would occupy commanding positions; then establish the camps, under cover from the fire of the enemy but as near up as possible; and then construct rifle-pits and covered ways, to connect the entire command by the shortest route. The enemy did not harass us much while we were constructing our batteries. Probably their artillery ammunition was short; and their infantry was kept down by our sharpshooters, who were always on the alert and ready to fire at a head whenever it showed itself above the rebel works.
