Immediately on the right of the Charleroi road, and in rear of ALTEN's Division, the First or Household Brigade, under Major General Lord EDWARD SOMERSET, was drawn up. It comprised the 1st and 2nd Life Guards, the Royal Horse Guards (Blue), and the 1st Dragoon Guards. On the left of the Charleroi road, and in rear of PICTON's Division, stood the Second Brigade, under Major General Sir WILLIAM PONSONBY; consisting of the 1st Dragoons (Royals), the 2nd Dragoons (Scots Greys), and the 6th Dragoons (Inniskillings). The Fourth and Sixth Brigades, under Major Generals Sir JOHN VANDELEUR and Sir HUSSEY VIVIAN, were posted upon the extreme Left of the main Line of the position, as previously explained. * * * * * The Reserves consisted of the Dutch-Belgian Cavalry Division, under Lieutenant General Baron COLLAERT; of the Brunswick Corps, comprising both Cavalry and Infantry, the command of which, since the fall of the Duke, had devolved upon Colonel OLFERMANN; and of the Tenth British Brigade, under Major General Sir JOHN LAMBERT. The latter formed part of the Sixth Division, commanded by Lieutenant General the Hon. Sir LOWRY COLE; and had only just reached the Field, after having performed forced marches from Ghent. COLLAERT's Division was stationed in rear of the Centre, and within the angle formed by the junction of the high roads leading from Charleroi and Nivelles. It comprised the First Brigade, commanded by Major General TRIP, and consisting of the 1st Dutch Carabiniers, the 2nd Belgian Carabiniers, and the 3rd Dutch Carabiniers; the Second Brigade, commanded by Major General GHIGNY, and consisting of the 4th Dutch Dragoons, and the 8th Belgian Hussars; and the Third Brigade, commanded by Major General VAN MERLEN, and consisting of the 5th Belgian Light Dragoons, and the 6th Dutch Hussars. The Brunswick Corps was posted between the northern portion of the Village of Merbe Braine and the Nivelles road, on which its Left rested; and comprised the following troops:--a Regiment of Hussars, a Squadron of Lancers, the Advanced Guard Battalion (which was at this time detached to the right of Merbe Braine); a Light Infantry Brigade, under Lieutenant Colonel BUTTLAR, consisting of the Guard Battalion, and the 1st, 2nd, and 3rd Light Battalions; and an Infantry Brigade, under Lieutenant Colonel SPECHT, consisting of the 1st, 2nd, and 3rd Line Battalions. LAMBERT's Brigade was posted near the Farm of Mont St Jean; and consisted of the 4th Regiment (under Lieutenant Colonel BROOKE), of the 27th Regiment (under Major HARE), and of the 40th Regiment (under Major HEYLAND).