At half past eleven o'clock in the forenoon of the 15th, another despatch was forwarded to BÜLOW from Namur, announcing the advance of the French, and requesting that the Fourth Corps, after having rested at Hannut, should commence its march upon Gembloux, by daybreak of the 16th at latest. The Orderly who carried it was directed to proceed to Hannut, the presumed Head Quarters of BÜLOW's Corps on that day. On reaching that place, the Orderly found the previous despatch lying in readiness for the General, and, mounting a fresh horse, he then went on with both despatches to Liege, where he arrived at sunrise. The Orders which they contained had now, however, become impracticable, in consequence of BÜLOW's not having immediately carried into effect the _first_ Order to collect at Hannut; and thus by one of those mischances, which, in war, occasionally mar the best planned operations, the opportune arrival of the Fourth Prussian Corps at the Battle of Ligny, which would, in all probability, have changed the aspect of affairs, was rendered a matter of impossibility. Late in the evening, and after Prince BLÜCHER had established his Head Quarters at Sombref, Captain BELOW arrived with the before mentioned report from Count BÜLOW; on receiving which his Highness was made sensible that he could no longer calculate with certainty upon being joined by the Fourth Corps on the following day. * * * * * It was seven o'clock in the evening of the 15th, when Marshal NEY, who had just arrived, joined the Emperor near Charleroi, at the point where the road to Fleurus branches off from the one to Brussels. Having expressed the pleasure he felt at seeing him, NAPOLEON gave him the command of the First and Second _Corps d'Armée_; explaining at the same time that REILLE was advancing with three Divisions upon Gosselies; that D'ERLON would pass the night at Marchienne au Pont; that he would find under his orders PIRÉ's Light Cavalry Division; as also the two Regiments of _Chasseurs_ and Lancers of the Guard, of which, however, he was not to make use except as a Reserve. "Tomorrow," added the Emperor, "you will be joined by the Reserve Corps of Heavy Cavalry under KELLERMANN. Go and drive back the Enemy." * * * * * It has already been shown in the preceding Chapter, that the extreme Left of the Duke of WELLINGTON's Army, composed of DE PERPONCHER's Second Dutch-Belgian Division, rested upon the Charleroi road to Brussels. The Second Brigade of this Division, under Colonel GÖDECKE, was thus located:--1st Battalion of the 2nd Regiment of Nassau, at Hautain le Val; the 2nd Battalion, at Frasne and Villers Peruin; the 3rd Battalion, at Bezy, Sart à Mavelines, and Quatre Bras; both Battalions of the Regiment of Orange-Nassau, at Genappe. There was also at Frasne a Dutch Battery of Horse Artillery, under Captain BYLEVELD.