The Third Dutch-Belgian Light Cavalry Brigade, under General VAN MERLEN, had shortly before this reached the Field, and now advanced to the support of the Dutch Infantry retiring from Gemioncourt; but they were met and defeated by PIRÉ's Cavalry, and pursued along the high road nearly to Quatre Bras, where they arrived in great disorder; a portion of them coming in contact with the Duke of WELLINGTON himself, and carrying his Grace along with them to the rear of Quatre Bras. The latter, however, succeeded in arresting their further flight, and in bringing them again to the front. The French Cavalry did not, on this occasion, follow up the pursuit, evidently hesitating to approach very near to the Allied Infantry, the latter appearing well formed, and fully prepared to receive them. The Dutch-Belgian Infantry retreated to the Wood of Bossu, abandoning four guns to the Enemy, who closely pursued them, and now began to penetrate into the Wood. Meanwhile, BACHELU, on the French Right, threw a considerable force into Piermont in sufficient time to secure its possession before the 1st Battalion 95th British Regiment had approached the Village, and was pushing forward another strong body towards a small Wood that lay still more in advance, on the opposite side of the Namur high road, the possession of which along with that of Piermont would have effectually cut off the direct communication between Quatre Bras and Ligny. Here, for the first time in this Campaign, the troops of the two nations became engaged. The Skirmishers who successfully checked the further advance of the French, and secured the Wood, were the 1st Battalion of the British 95th Rifles, whom the old Campaigners of the French Army, at least those who had served in the Peninsula, had so frequently found the foremost in the fight, and of whose peculiarly effective discipline and admirable training they had had ample experience. The possession of Gemioncourt proved of the utmost importance to NEY's position, which now assumed a definite character, and, in a purely tactical point of view, offered great advantages. The southern portion of the Wood of Bossu was occupied by his extreme Left, while his extreme Right was in full possession of Piermont; and these points were connected by a narrow valley extending along his whole front, bounded on either side by a hedgerow, and intersecting the Charleroi road close to Gemioncourt. The outer fence was strongly occupied by his Light Troops, ready to cover the formation and advance of his Columns of Attack, for the support of which by Artillery, the Heights constituting his main position in rear of Gemioncourt, offered every facility.