[288] east, laves their base, to follow afterward a southerly direction. The upper batteries enfiladed the river above. A little lower down the heights fade away from the bank upon which the little town of Grand Gulf is situated. Below this town Bowen had erected a second line of batteries, which commanded the railway from Grand Gulf to Port Gibson. At this angle the depth of the river is too great to admit of any anchorage. The current is extremely rapid: in the middle of the stream it attains a speed of six knots, while along the bank violent eddies render navigation very difficult. The Confederates, taught by their experience at Vicksburg, had erected no battery at the water's edge: all their cannons lined the summit of the cliffs at a height which it was difficult for the gunboats to reach, and where their simple recoil was sufficient to protect them against any direct fire.
The task of Porter, who was ordered to reduce these batteries, was therefore a difficult one. He despatched four vesssels, the Pittsburg, the Louisville, the Mound City, and the Carondelet, to attack the lower batteries, whilst with the Benton, the Tuscumbia, and the La Fayette he opened fire upon the upper works. The vessels, finding it impossible to obtain a mooring, were obliged to fight under steam, while the current, driving them constantly among the eddies, imparted such irregularity to their motions as to affect the precision of their aim. In the mean while, the fire of the lower batteries, much less protected than the others, was silenced after a bombardment of three hours, the gunners being obliged to abandon their pieces, although they were not dismounted. The four ships which had attacked them then reascended the river in order to assist the rest of the squadron. In fact, the admiral had not met with the same success against the upper batteries, which, although riddled with balls, were still replying with great vigor. For a moment, it is true, they had ceased firing, and were thought to be silenced. The vessels with Osterhaus' division on board had even received from Grant the signal agreed upon, and had come forward for the purpose of landing his force upon the enemy's shore. Fortunately for the Federals, this imprudent manoeuvre was promptly stopped by the renewal of hostilities, and the transports were able to get away with their precious cargo before being exposed to the projectiles
