When the Centre of the Prussian Army had been broken by the French Cavalry, and the Prussian Commander had been placed so completely _hors de combat_, Lieutenant General Count VON GNEISENAU, the Chief of the Staff, having undertaken the direction of affairs, ordered the retreat of the First and Second Corps upon Tilly; and despatched Colonel THILE with directions to THIELEMANN, that if he could not effect a direct retreat upon Tilly, he was to retire upon Gembloux, there to unite with BÜLOW, and then effect a junction with the rest of the Army. The occupation of Bry by General PIRCH II. offered a safe point of retreat to the disordered Prussian Battalions; and, now that it had become quite dark, PIRCH led all the troops from this post towards Marbais, where they reformed, and whence, soon afterwards, under the command of Lieutenant General RÖDER, they continued the retreat upon Tilly. MARWITZ' Cavalry Brigade, which was not pursued with much vigour by the Enemy, fell back to the rear of the Battalions formed up to cover its movement, and now joined the rest of the Cavalry of the Right Wing, in the general retreat. The Fifth Infantry Brigade was in full retreat upon Marbais when the 1st and 2nd Battalions of the 22nd Regiment still continued posted on the high road, not far from the Trois Burettes. The good order and perfect steadiness of these Battalions, which were commanded by Major SACK, completely checked the further advance of the French Cavalry, and greatly facilitated the retreat of the Prussian troops. After General JÜRGASS was wounded, the command of the Rear Guard devolved upon Lieutenant Colonel SOHR, of whose Brigade (the Brandenburg and Pomeranian Hussars) it consisted. He executed this duty with great success, falling gradually back upon the Cavalry posted in advance of Tilly by Lieutenant General ZIETEN; who then took command of the whole of the Cavalry employed in protecting the retreat. * * * * * During the retreat of the Centre of the Prussian Army, which had been effectually broken, and of its Right from St Amand and Wagnelé, which, in consequence of BLÜCHER's previous dispositions for his contemplated attack upon the French Left, was better prepared to sustain a reverse of this kind; the Left Wing, under THIELEMANN, maintained its position, and contributed not a little, by its firm countenance, in diffusing a considerable degree of caution into the French movements in advance.