In the mean time the Brunswick Hussars were ordered forward to cover the retreat of the Infantry, and repel the advance of the French Cavalry, which was now seen in rapid motion along the Charleroi road, as if incited and emboldened by the loud shouts of triumph sent forth by their Light Troops in front. The Hussars, whose order while advancing, was quickly disturbed by a straggling fire from the French Infantry, to which their Right Flank became exposed, failed in producing the slightest check upon the Cavalry, and were soon seen wheeling about and in full flight, closely pursued by their opponents. To the 42nd Highlanders and 44th British Regiment, which were posted on a reverse slope, and in line, close upon the left of the above road, the advance of French Cavalry was so sudden and unexpected, the more so as the Brunswickers had just moved on to the front, that as both these bodies whirled past them to the rear, in such close proximity to each other, they were, for the moment, considered to consist of one mass of Allied Cavalry. Some of the old soldiers of both Regiments were not so easily satisfied on this point, and immediately opened a partial fire obliquely upon the French Lancers, which, however, Sir DENIS PACK and their own Officers endeavoured as much as possible to restrain; but no sooner had the latter succeeded in causing a cessation of the fire, than the Lancers, which were the rearmost of the Cavalry, wheeled sharply round, and advanced in admirable order directly upon the rear of the two British Regiments. The 42nd Highlanders having, from their position, been the first to recognise them as a part of the Enemy's forces, rapidly formed Square; but just as the two Flank Companies were running in to form the rear face, the Lancers had reached the Regiment, when a considerable portion of their leading division penetrated the Square, carrying along with them, by the impetus of their charge, several men of those two Companies, and creating a momentary confusion. The long tried discipline and steadiness of the Highlanders, however, did not forsake them at this most critical juncture: these Lancers, instead of effecting the destruction of the Square, were themselves fairly hemmed into it, and either bayoneted or taken prisoners, while the endangered face, restored as if by magic, successfully repelled all further attempts on the part of the French to complete their expected triumph. Their Commanding Officer, Lieutenant Colonel Sir ROBERT MACARA, was killed on this occasion, a lance having pierced through his chin until it reached the brain; and within the brief space of a few minutes, the command of the Regiment devolved upon three other Officers in succession: Lieutenant Colonel DICK, who was severely wounded, Brevet Major DAVIDSON, who was mortally wounded, and Brevet Major CAMPBELL, who commanded it during the remainder of the Campaign.