In order more effectually to mask the movements on the Allied side of the Namur road, the whole of the Cavalry was drawn up in two lines immediately contiguous to, and in rear of, that road; the Heavy Cavalry forming the Second Line, and Picquets being thrown out from the First Line, to relieve those of the retiring Infantry. The main body of ALTEN's Division now commenced its further retreat; but not by alternate Brigades, this mode having been directed only in the event of an attack; the latter retired successively in the order in which they stood, preserving their relative distances, so that they might commence the alternate system of retreat, if attacked. To facilitate the passage of other portions of the Army through the narrow defile of the bridge and town of Genappe, this Division retired by Bezy, and crossed the Genappe, lower down the stream, by the bridge of Wais le Hutte. * * * * * In the early part of the morning, NEY had, like his opponent, been ignorant of the result of the Battle of Ligny; but he was aware that the Anglo-Allied Army had been considerably reinforced during the night, principally by the arrival of its Cavalry. The Marshal calculated that if NAPOLEON had gained a victory, and crossed the Namur road, the longer WELLINGTON remained in the position of Quatre Bras, the greater the danger he incurred of having not only his communication with BLÜCHER effectually cut off, but also his main line of retreat upon Brussels intercepted; and that in such a case it was wiser not to advance against the British General, as the latter might then retire, and thus elude the effect of a combined operation between NAPOLEON's and his own forces. He also judged that if, on the other hand, the French Emperor had been defeated, an attack made on his own part, upon the Anglo-Allied Army, might subject himself to the risk of having to contend against a combined operation between WELLINGTON and BLÜCHER; and thus expose both his own and NAPOLEON's forces to the probability of being defeated in detail. In this uncertainty, NEY sent a message by General Count FLAHAUT, who happened to be still with him, and who was returning to rejoin the Emperor wherever he might be found, expressive of his anxiety to learn the result of the action of the preceding day. In the mean time, he kept his troops in a state of perfect quietude; his main body was posted in reserve on the Heights of Frasne, between which and the Outposts there were intermediate Columns of Support; but no movement whatever was attempted.