There is a striking contrast between the march of Grouchy's large detachment, in pursuit of a defeated army, which had commenced its retreat on the previous night, and which presented no check to the advance, and the march of Napoleon from the same battlefield, by Quatre Bras and Genappe, as far as La Belle Alliance, in front of the Waterloo position, a distance of about 16 miles ; and this, too, in rear of a victorious army, with a cavalry rearguard boldly and successfully impeding the advance of its pursuers.