The French Light Troops moved forward against Fleurus, of which place they gained possession between eleven and twelve o'clock, and then opened from their Light Artillery a cannonade upon the Prussian Cavalry Posts taken up by the 6th Uhlans. The latter immediately retired, and formed upon the left of the Brandenburg Dragoons, which Regiment had been placed in front of the Tombe de Ligny, along with the Horse Battery No. 2, in support. The Brandenburg Uhlans were also in support, but more to the rear, and on the left of the high road. At this time, NAPOLEON was on the Height of Fleurus, again reconnoitring the Prussian position; and it was also about the same period that WELLINGTON joined BLÜCHER in person near the Mill of Bussy. As soon as RÖDER perceived the imposing array of the French Columns in full advance, he ordered the immediate retreat of his Cavalry, which he covered with the 6th Uhlans and the Brandenburg Dragoons, together with two pieces of Horse Artillery. He sent the main body, which he had stationed in a hollow, in rear of the Tombe de Ligny, as also the remainder of the Artillery, across the Ligny, with directions to take post between the Village of that name and Sombref. He himself continued with the above two Regiments, and the two guns, near the Tombe de Ligny, until he received Orders also to retire. * * * * * In the mean time, the main body of the French Army advanced in great regularity in Columns of Corps. The Left Column, consisting of the Third _Corps d'Armée_ under VANDAMME, to which was attached the Infantry Division under Lieutenant General GIRARD belonging to REILLE's Corps (then with NEY), being destined to advance against St Amand, the most salient point of the Prussian position, and therefore having the shortest distance to pass over, was the first to take up its ground, preparatory to attack. Whilst thus engaged in making its preliminary dispositions for this purpose, it was cannonaded by the Prussian Batteries posted on the Heights in rear of the Village. GIRARD's Division took post on the left of VANDAMME's Corps, and DOMON's Light Cavalry Division on the left of GIRARD. The Centre Column, consisting of the Fourth _Corps d'Armée_, under GÉRARD, advanced along the Fleurus high road, and took up, somewhat later, a position upon the Heights fronting Ligny, and parallel to the general direction of that Village; its Left being near the Tombe de Ligny, and its Right resting on an eminence southward of Mont Potriaux.