By the determined show of resistance which his Serene Highness displayed, as well as by the vigorous cannonade which he maintained, PIRÉ's Advanced Guard, the Left Flank of which became endangered by the Dutch occupying the Wood of Bossu, was forced to retire in its turn, which it did unmolested, and brought back intelligence that Quatre Bras was occupied by ten Battalions with Artillery, and that WELLINGTON's troops were moving to concentrate at this important point. At ten o'clock at night, NEY's forces were thus disposed:--PIRÉ's Light Cavalry Division and BACHELU's Infantry Division occupied Frasne, a village situated upon the Brussels road, about two miles and a half on the French side of Quatre Bras; the two Regiments of _Chasseurs_ and Lancers of the Guard were in reserve in rear of Frasne; REILLE was with two Divisions, and the Artillery attached to them, at Gosselies: these Divisions ensured the communication until the arrival of D'ERLON's Corps, which was to remain that night at Marchienne au Pont. The remaining Division of REILLE's Corps (GIRARD's) was at Heppignies, and thus served to maintain the communication with the Main Column under NAPOLEON. The troops were greatly fatigued by having been kept constantly on the march since three o'clock in the morning; the strength of the different Regiments, the names of their Colonels, and even of the Generals, were unknown to the Marshal, as also the number of men that had been able to keep up with the heads of the Columns at the end of this long march. These circumstances, combined with the information brought in from Quatre Bras, induced NEY to decline risking a night attack upon that point; and he contented himself with taking up a position in advance of Frasne. Having issued such Orders as he deemed essential, and enjoined the most vigilant look out, he returned to Charleroi, where he arrived about midnight; partook of supper with NAPOLEON (who had just arrived from the Right Wing of the Army), and conferred with the Emperor upon the state of affairs until two o'clock in the morning. * * * * * The first intimation which the Duke of WELLINGTON received on the 15th, of hostilities having commenced, was conveyed in the report already alluded to, as having been forwarded by General ZIETEN, shortly before five o'clock in the morning, and as having reached Brussels at nine o'clock. It was not, however, of a nature to enable the Duke to form an opinion as to any real attack being contemplated by the Enemy in that quarter. It simply announced that the Prussian Outposts in front of Charleroi were engaged. It might be the commencement of a real attack in this direction, but it might also be a diversion in favour of an attack in some other direction, such as Mons. In fact, until further information was received, it could only be considered in the light of an affair of Outposts.