About 6 o'clock there was disorder in a great part of the Duke of Wellington's army. The ranks were thinned by the number killed, by those carried off wounded, and by desertions. Soldiers of various nations, Belgian, Hanoverian and English "crowded to the rear" and fled in a panic from this dreadful action. "A number of our own dismounted dragoons" says Captain Pringle, "together with a portion of our infantry, were glad to escape from the field. These thronged the road leading to Brussels, in a manner that none but an eye-witness could have believed."
Cries of "Victory!" now resounded from the French over different parts of the field. Napoleon on hearing this, observed,—"It is an hour too soon; but we must support what is done." He then sent an order for a grand charge of three thousand cuirassiers under Kellerman on the left, and who were to move forward briskly and support the cavalry on the low grounds.
A distant cannonade was now heard in the direction of Wavres. It announced the approach of Grouchy—or Blucher!
At 12:30 o'clock Grouchy was midway between Gembloux and Wavres. The tremendous cannonade of Waterloo resounded from the distance. General Excelmans rode up to the marshal, and told him that "he was convinced that the Emperor must be in action with the Anglo-Belgian army; that so terrible a fire could not be an affair of outposts or skirmishing; and that they ought to march to the scene of action, which, by turning to the left, they might reach within two hours."
Grouchy paused awhile, and then reverted to his orders to follow Blucher, although he did not know where Blucher really was. Count Girard came up, and joined in the advice of General Excelmans. Still Grouchy remained doubtful, and as if stupefied. "At one moment" says Hazlitt "he appeared convinced; but just then a report came that the Prussians were at Wavres, and he set out once more after them," instead of instantly hurrying off to join the Emperor in his great battle.
It was a rear-guard which Blucher had left at Wavres; and the Prussian leader had gone to Waterloo, at the head of 30,000 men, having been advised, as previously stated, that the Duke of Wellington would hazard a battle on the morning of the 18th, if he could depend on the co-operation of the Prussians. The veteran marshal, at an early hour, had detached the corps of Bulow, with orders to march on St. Lambert, leaving Mielman with his corps at Wavres.
The Duke had expected to be joined by Blucher as early as 11 o'clock; but the roads were in such a condition that the Prussians could not accomplish the march in any such time as had been calculated. Their advance was necessarily slow,—but it was in the right direction!
Meanwhile, the Emperor on the battlefield of Waterloo, had reluctantly ordered the charge of Kellerman's three thousand cuirassiers, asked for by Ney, to sustain and follow up the advantage of the cuirassiers of Milhaud and the chasseurs of the Guard, on the plain below. The marshal's contest had been carefully watched by Napoleon who declared at once that Ney was too impatient, and had begun an hour too soon. "This man is always the same." said Marshal Soult. "He will compromise everything as he did at Jena and Eylau."
Kellerman was now all ready for action, but he condemned the desperate use which at this moment was to be made of the cavalry. Distrusting the result, he kept back one of his brigades, the carbineers, and most unwillingly sent the remainder to Ney, whom he accused of foolish zeal.
These twenty squadrons, led on by their generals and officers, now advanced at full gallop as if in pursuit of the English army, shouting, "Vive l'Empereur!" and under the cannonade of the Prussians, for Bulow was still pressing upon the flank and rear. Other bodies of cavalry also advanced upon the centre of the Anglo-Belgian army, making a spectacle which General Foy, an eye-witness, afterwards declared that during his long military career he had never been present at such a fearful scene as he then beheld.