The cavalry force was small, but energetic and enterprising to a degree as yet by no means equalled by our own. The artillery was neither as good, nor as well equipped or served, as ours, but was commanded with intelligence, and able to give a good account of itself. V. DIFFICULTY OF AN ATTACK. An attack of Lee's position in front, even had Burnside's experience not demonstrated its folly, seemed to promise great loss of life without corresponding success. To turn his right flank required the moving of pontoon trains and artillery over the worst of roads for at least twenty miles, through a country cut up by a multitude of streams running across the route to be taken, and emptying into either the Potomac or Rappahannock; all requiring more or less bridging. Lee's spy system was excellent. It has been claimed in Southern reports, that his staff had deciphered our signal code by watching a station at Stafford. And Butterfield admits this in one of his despatches of May 3. He would speedily ascertain any such movement, and could create formidable intrenchments on one side the river, as fast as we could build or repair roads on which to move down, upon the other. Moreover, there was a thousand feet of stream to bridge at the first available place below Skenker's Neck. There remained nothing to do but to turn Lee's left flank; and this could only be accomplished by stratagem, for Lee had strengthened every part of the river by which Hooker could attempt a passage. But this problem was, despite its difficulties, still possible of solution; and Hooker set himself to work to elucidate it. So soon as he had matured his plan, which he elaborated with the greatest care, but kept perfectly secret from every one until the movements themselves developed it, although making use of the knowledge and skill of all his generals both before and during its initiation, he speedily prepared for its vigorous execution. In May, the term of service of some twenty-two thousand nine-months and two-years men would expire. These men he must seek to utilize in the campaign. The first intimation of a forward movement received by the army at large, apart from the Cavalry Corps, had been a circular of April 13, notifying commanding officers to have their troops supplied with eight days' rations, and a hundred and fifty rounds of ammunition, sixty to be carried by the soldiers, and the balance on the pack-mules.