[355] part of skirmishers and recommended the artillerymen to be sparing of their powder. In his situation this was a necessary precaution, but it enabled Grant's army during the days of the 20th and 21st to draw closer to the works and rectify its positions with impunity.
The Federal fleet, on the contrary, never ceased firing shells and bombs, which killed many people, dismounted several guns, and caused much damage to the city. Yet the inhabitants refused to leave it, preferring to make their homes in caves cut in the sides of the ravines, after the manner of the Egyptian tombs, where they were sheltered from the enemy's projectiles. A large number of horses and mules, having become useless, were driven out of the works, but the Federal soldiers amused themselves with shooting them between the two lines, and their carcasses, being exposed to a torrid sun, soon poisoned the air that was breathed by both besieged and besiegers alike.
The general assault was fixed for the 22d at ten o'clock in the morning: the corps commanders had regulated their watches so as to secure greater unanimity to the movement. They were to make their troops advance at once in columns of platoons over all the roads leading to Vicksburg, north-east, east, and south-east. Believing that they had failed on the 19th because the attacks had been limited to those portions of the enemy's line adjoining the roads, they had carefully examined all this line during the two following days, and selected new points of attack. The crews of the vessels which had remained above planted six mortars on large rafts moored close to the bank, so as to be able to fire into the works over the strip of land and the turning-point in the river. These mortars fired bombshells during the entire night, and at seven o'clock in the morning Porter came with the iron-clads1 that were lying below Vicksburg to place himself within four hundred and forty yards of the lower batteries, upon which he poured a shower of shot. From three o'clock in the morning Grant's artillery had made Pemberton aware of the attack that was preparing against him. When daylight appeared the skirmishers, advancing as close as possible along the edge of the woods and among the ravines, which afforded them some shelter,
