Shortly before five o'clock, he despatched _Courier Jägers_ to their respective Head Quarters, Brussels and Namur, with letters containing the information that since half past four o'clock, he had heard several cannon shots fired in his front, and at the time he was writing, the fire of musketry also, but that he had not yet received any report from his Outposts. To BLÜCHER he at the same time intimated that he should direct the whole Corps to fall back into position; and, should it become absolutely necessary, to concentrate at Fleurus. His report to the Duke of WELLINGTON arrived in Brussels at nine o'clock in the morning; that to Prince BLÜCHER reached Namur between eight and nine o'clock. The former, while it placed the British Commander on the _qui vive_, did not induce him to adopt any particular measure--he awaited further and more definite information; but the latter satisfied the Prussian Field Marshal that he had taken a wise precaution in having already ordered the concentration of his several Corps in the position of Sombref. The Prussian troops at Maladrie checked, for a time, the advance of the French upon Thuin, and maintained their ground for more than an hour, with the greatest bravery. They were overpowered, and driven back upon Thuin. This place was occupied by the 3rd Battalion of the 2nd Westphalian Landwehr, under Major MONSTERBERG, who, after an obstinate and gallant resistance, during which the Battalion suffered an immense loss, was forced to retire, about seven o'clock, upon Montigny, where he found Lieutenant Colonel WOISKY, with two Squadrons of the 1st West Prussian Dragoons. The French succeeded in taking this village, and the retreat was then continued in good order, under the protection of WOISKY's Dragoons, towards Marchienne au Pont; but before reaching this place, the latter were attacked, and completely overthrown by the French Cavalry; and the Infantry getting into disorder at the same moment were partly cut down, and many were taken prisoners. Indeed so severe was the loss which the 3rd Battalion of the 2nd Westphalian Landwehr suffered in this retreat, that the mere handful of men which remained could not possibly be looked upon as constituting a Battalion in the proper meaning of the term. It was reduced to a mere skeleton. Lieutenant Colonel WOISKY was wounded on this occasion; but continued, nevertheless, at the head of his Dragoons. Captain GILLHAUSEN, who, as before stated, commanded the Prussian Battalion posted at Lobbes, as soon as he had satisfied himself that Thuin was taken, saw the necessity of effecting his own retreat, which he did, after the lapse of half an hour, drawing in his Picquets, and occupying the Bridge over the Sambre with one Company. He then fell back, and occupied the Wood of Sar de Lobbes, where he received an Order, as soon as the Post of Hoarbes was also taken by the Enemy, to continue his retreat, taking a direction between Fontaine l'Evêque and Anderlues.