At length the 7th Hussars retired through Genappe, after having thrown out their Right Squadron, commanded by Major HODGE, as Rear Guard, to cover the retreat of the Centre Column, regulating its proceedings in conformity with such Orders as it might receive from Major General Sir WILLIAM DÖRNBERG, who had been desired to superintend the movements of the Skirmishers. Major HODGE led out the Right Troop, under Captain ELPHINSTONE, to skirmish, while Lieutenant STANDISH O'GRADY, who commanded the Left Troop, held the high road, from which he had occasionally to send assistance to the former, and frequently to advance, to enable the Skirmishers to hold their ground, as their movements were difficult, through ploughed fields so soft that the horses always sank up to their knees, and sometimes to their girths. In this manner, every inch of ground was disputed, until within a short distance of Genappe. Here DÖRNBERG informed Lieutenant O'GRADY that he must leave him; that it was of the utmost importance to face the Enemy boldly at this spot, as the Bridge in the town of Genappe was so narrow that the Squadron would have to pass it in file; that he was to endeavour as much as possible to obtain time for drawing off the Skirmishers, but not to compromise his Troop too much. Lieutenant O'GRADY then called in his Skirmishers, and advanced with his own Troop boldly up the road at a trot. The Cavalry immediately opposed to him, went about, followed by him for some distance; and he thus continued alternately advancing and retiring, until he saw all the Right Troop safe on the road in his rear. He then began to retire at a walk, occasionally halting and fronting, until he turned the corner of the town of Genappe: when he filed the men from the left, and passed through the place at a gallop. Upon the arrival of the Squadron at the opposite entrance of Genappe, it was posted between this point and the main body of the 7th Hussars, which had been drawn up on the road in a column of divisions, prepared to check the advance of the Enemy on his debouching from the town.