The army, 32,000 strong, under General W.T. Sherman, had arrived on the 26th, and landed on the low ground above the old mouth of the Yazoo, the gunboats occupying the sweep of river around them for a length of eight miles. Heavy rains had set in, making the ground almost impassable and causing the water to rise. After various preliminary operations the troops assaulted the works on the hills in front on the 29th, but the attack failed entirely. Sherman considered the works too strong to justify its renewal at the same point, but determined to hold his ground and make a night assault with 10,000 men higher up the river, upon the right of the Confederate works at Haines's Bluff, where the navy could get near enough to try and silence the batteries. Colonel Charles Rivers Ellet,[14] of the ram fleet, volunteered to go ahead with the ram Lioness and attempt to blow up a raft which was laid across the stream. Everything was ready on the night of the 31st, but a dense fog setting in prevented the movement. The continued rains now rendered the position of the army dangerous, and it was re-embarked on the 2d of January. The enemy apparently did not discover the movement till it was nearly finished, when they sent down three regiments with field pieces to attack the transports, a movement quickly checked by the fire of the gunboats. When Sherman's army was embarked, the transports moved out into the Mississippi and anchored five miles above Vicksburg, where General McClernand joined and assumed the chief command. Soon after his arrival he determined upon a movement against Fort Hindman, on the Arkansas River, fifty miles from its mouth. This point, better known as Arkansas Post, commanded the approach to Little Rock, the capital of Arkansas, but was specially obnoxious to the Union forces at this time, as being the base from which frequent small expeditions were sent out to embarrass their communications by the line of the Mississippi, from which it was but fifteen miles distant in a straight line. A few days before, the capture of the Blue Wing, a transport loaded with valuable stores, had emphasized the necessity of destroying a work that occupied such a menacing position upon the flank and rear of the projected movement against Vicksburg. The admiral detailed the three ironclads, De Kalb, Louisville, and Cincinnati, and all the light-draught gunboats to accompany the expedition; the gunboats, on account of their low speed, being taken in tow by the transports. Passing by the mouth of the Arkansas, to keep the enemy as long as possible uncertain as to the real object of the movement, the fleet entered the White River and from the latter passed through the cut-off which unites it with the Arkansas.