As Lobau's Corps advanced and passed Domon's Cavalry, the latter was disposed as a Support. Having crossed the valley which, commencing from the ridge above Planchenoit, on the north side of the Village, descends towards Smohain, he opened a brisk fire from his guns upon Bülow's Line. A spirited cannonade ensued, in the course of which the Prussian Foot Battery No. 14 had three guns disabled.
It was not long, however, before the remaining Brigades of Bülow's Corps, the Thirteenth and Fourteenth, came up. Their Batteries hastened to the front, and materially increased the force of the Prussian fire.
Blücher, who had now the whole of Bülow's Corps at his disposal, was bent upon following up his original intention of directing his attack against the Enemy's Rear. With this view he made the Sixteenth Brigade take ground to its left, and brought up the Fourteenth Brigade in its rear, as a Support; whilst at the same time he supplied the place of the former in the Line by posting the Thirteenth Brigade on the left of the Fifteenth. General Hacke, who commanded the Thirteenth Brigade, detached the 1st and 3rd Battalions of the Second Neumark Landwehr to the right, in support of the troops in Smohain. A portion of this Detachment occupied Frischermont, thus obtaining an appui for the Prussian Right Flank, and securing the communication with the Prince of Saxe Weimar's Brigade, posted along the inclosures in front of the extreme Left of the Anglo-Allied Army. This Flank was also covered by the West Prussian Uhlans and the 2nd Neumark Landwehr Cavalry, that had been detached from the Reserve Cavalry of the Fourth Corps under Prince William of Prussia; which was following, as a Support, the Left Wing of Bülow's Line, now advancing in the direction of Planchenoit. The Artillery along the Prussian Line had by this time assumed a formidable appearance, the following Batteries of the Corps having come successively into action,—the twelve pounder Batteries Nos. 3 and 5, the six pounder Batteries Nos. 2, 13, 14, and 21, and the Horse Batteries Nos. 11 and 12—comprising altogether sixty four guns.
The ground over which Bülow's Corps was now in the act of advancing, was highly favourable for the development of a force destined to attack the Flank of an Army, the Front of which was so completely aux prises with the Enemy as was that of the French at this moment. Nearly at all points it commanded the position occupied by the French Right en potence; the Line was remarkably well appui'd on the Flanks; and its Front was parallel with the Enemy's main line of operation.
The force which Lobau had at his disposal was greatly inferior to that of the Corps he was sent to oppose. The former amounted to fifteen Battalions, twenty one Squadrons, and forty two guns—the latter (exclusive of the six Battalions and eight Squadrons detached to the right) consisted of thirty Battalions, twenty seven Squadrons, and sixty four guns. He could not present a Front sufficiently extensive and compact that would secure him from being turned in either Flank. Hence, when he perceived that the principal force in this well planned attack was advancing from the Prussian Left, in the direction of Planchenoit, which then lay in his right rear, unoccupied by any French troops; he felt the necessity of retiring towards the Charleroi road, which he did by withdrawing his Brigades en échiquier.
It was not long before several round shot from the Prussian Batteries reached the Charleroi road; some of them falling both in front and rear of La Belle Alliance, where Napoleon was then stationed. It was evident to the latter that, unless reinforcements were despatched in support of Lobau, his Right Flank, already so seriously menaced, would speedily be turned. His trusty Guard with which, in former Campaigns, he had so frequently succeeded in stemming the current that had suddenly set in against him from some previously hidden source and threatened to overwhelm him, constituted the sole Reserve at his disposal. Engaged during so many hours in carrying on a desperate attack along his whole Front, without having as yet secured one single point of vantage ground; he clearly foresaw that without some vigorous effort, by aid of a powerful Reserve, no ray of victory would ever gleam upon his arms on that side of the Field. But now that he was also engaged in defensive operations along his Right, against another Enemy, by whom even his Rear and the main line of his retreat became endangered; the necessity of employing a portion of this Reserve in a direction different from that which he had contemplated, was alike obvious and urgent.
The appearance of Bülow's Left bearing down upon Planchenoit, turning Lobau's Right; and the powerful Batteries along the Prussian Front admirably disposed in accordance with the favourable nature of the ground, over which the whole Line was gradually approaching; distinctly indicated the immediate possession of that Village in force, as the true and only measure that could be adopted for averting the impending danger. The two Divisions of the Young Guard, posted on the plateau on the right of the chaussée close to Rosomme, and consisting of four Battalions of Voltigeurs, and four Battalions of Tirailleurs, were the nearest at hand for the occupation of Planchenoit; and Napoleon accordingly desired General Duhesme instantly to march thither with that force, accompanied by twenty four pieces of cannon of the Guard, and place himself on the right of Lobau's Corps.
It was about this time (six o'clock) that Napoleon replied to Ney's demand for fresh Infantry, Ou voulez vous que j'en prenne? Voulez vous que j'en fasse? an expression, the force of which is rendered sufficiently obvious by the critical circumstances of his position.