Thus it appears that both Commanders were deceived as to the proximity of any considerable body of Prussians at this period of the day. Nevertheless, the conviction of such a proximity, while it imparted increased confidence to WELLINGTON, in regard to the speedy execution of the plan of combined operation which he had preconcerted with BLÜCHER, compelled NAPOLEON to employ additional vigilance and circumspection upon his Right Flank. Great, however, as was the necessity for such vigilance; the measures that were adopted were lamentably deficient in energy, vigour, and judgement. Considering that the main body of BÜLOW's Corps was on the point of entering the Defile of St Lambert, in which it had to overcome the greatest difficulties; it appears unaccountable that the Officer employed in reconnoitring and patroling beyond the extreme Right of the French Army should not have urged the occupation of the Wood of Paris with a detached body of Infantry, with a view to impede BÜLOW's advance, and compel him to take a more circuitous route. In this manner the Prussian co-operation might have been so far obstructed or delayed as to secure to NAPOLEON the power of advancing against WELLINGTON with almost the entire of his force; and of thus, perhaps, accomplishing his grand object of defeating both Armies in detail. No disposition of this kind was made; but, in place of it, DOMON's and SUBERVIE's Light Cavalry Divisions were moved to the right, _en potence_ to the Front Line, their Picquets not extending beyond the plateau in front of the Wood of Paris. Whether this culpable neglect arose from the want of due penetration and foresight on the part of General DOMON; or from this Officer having been instructed not to act as if in command of a detached Corps, but only to take up a position, within a prescribed distance, _en potence_ to the general Front Line; or, from an over confident expectation on the part of NAPOLEON of approaching aid from GROUCHY; are points not easily determined: but there can be no doubt that the error of not occupying the Wood of Paris with a strong body of Infantry, flanked and supported by the Cavalry, was fatal to the development of NAPOLEON's original design. One Infantry Division, combined with Domon's and SUBERVIE's Cavalry Divisions, would have sufficed for obstructing the debouching of BÜLOW's Corps from the almost impassable Defile of St Lambert; and compelling it to move by its right, into the line of march of ZIETEN's Corps, which did not reach the field before seven o'clock in the evening. To move by its left, along the deep and miry valley of the Lasne, would have been impracticable so long as the Wood of Paris and its vicinity continued to be occupied by the French.