We have seen how Anderson engaged Meade near Chancellorsville as the latter advanced, and then retired to a position near Mine-Run road. Here was the crest of a hill running substantially north and south. Gen. Lee had already selected this line; and Col. Smith, his chief engineer, had drawn up a plan of intrenchments. Anderson detailed men, who, during the night, threw up some strong field-works. Late Thursday night Lee appears first fully to have matured his plan for parrying Hooker's thrust. Barksdale's brigade was left at Fredericksburg, where during the winter it had been doing picket-duty, to form the left of the line remaining to oppose Sedgwick. Part of Pendleton's reserve artillery was near by; while Early, commanding this entire body, held Hamilton's Crossing. He had a force of eighty-five hundred muskets, and thirty pieces of artillery. The rest of his army Lee at once took well in hand, and moved out to meet the Army of the Potomac. McLaws was hurried forward to sustain the line taken up by Anderson. He arrived on the ground by daylight of Friday, and went into position in rifle-pits on the right about Smith's Hill. Jackson, equally alert, but having a longer distance to march from the extreme right along the military road, arrived about eight A.M., took command, and, as was his wont, ordered an immediate advance, throwing Owens's regiment of cavalry forward to reconnoitre. Posey and Wright followed Owens on the plank road, with Alexander's battalion of artillery. Mahone, and Jordan's battery detached from Alexander, marched abreast of his right, on the pike. McLaws followed Mahone, and Wilcox and Perry were called from Banks's Ford to sustain this column, which McLaws directed; while Jackson, following on the plank road, watched the operations of the left. X. HOOKER'S ADVANCE FRIDAY. So far the headquarters of the Army of the Potomac had been at Falmouth, where still remained Gen. Butterfield, Hooker's chief of staff. The last order from this point had been on Thursday to Gen. Sedgwick, who was therein notified that headquarters would be that night at Chancellorsville; that an advance would be made Friday morning along the plank road (meaning probably the pike) towards Fredericksburg, to uncover Banks's Ford, thus making a shorter communication through Butterfield, who would still remain at Falmouth. This order substantially recapitulates former instructions, and is full of the flash and vim of an active mind, till then intent on its work and abreast of the situation. It urges on Sedgwick co-operation with the right wing, and the most vigorous pushing of the enemy. It impresses on him that both wings will be within easy communication, and ready to spring to one another's assistance.