As to the first, Grouchy was unaware that Excelmans, with his whole Corps, was already at Gembloux. But Pajol’s report from Le Mazy might have helped him to come to the conclusion that the Prussians had not taken that direction.
Grouchy, when he had received his verbal instructions from Napoleon, had expostulated and expressed the opinion that no advantage would be obtained if he carried out the operations he was ordered to. He argued that the Prussians had already had twelve hours’ start; that although no definite news had yet been received from the cavalry scouts, it was extremely likely that Blucher had retired on his base, Namur; and that in following the Prussians in this direction he would be moving further and further from Napoleon. He asked to be allowed to march to Quatre-Bras with the Emperor. But Napoleon, naturally enough, declined, and firmly repeated his orders to Grouchy, saying that it was his (Grouchy’s) duty to find which route the Prussians had taken, and to attack them as soon as he found them.
Grouchy withdrew and proceeded to carry out his orders. But if he was so far convinced of the importance and infallibility of his own conclusions as to discuss them boldly before the Emperor, he certainly could not have been very hopeful or determined when he proceeded to carry out the very instructions against which he had been arguing!
He then sent orders to Vandamme, who was at St Amand, to march at once with the Third Corps to Point-du-Jour, at the junction of the Gembloux and Namur roads. He sent an aide-de-camp towards Gembloux to obtain news from Excelmans. (Not often is it necessary for a general to send one of his own Staff to gather news from the advanced cavalry!) He then went himself to Ligny to give Gérard his orders.
In starting Vandamme before Gérard, Grouchy made a serious mistake; for Gérard had over an hour to wait before he could march his troops off, since both Corps had to use the same road, and Vandamme was behind Gérard at the time. Vandamme’s Corps had suffered less than Gérard’s at Ligny the day before, but it was no longer a case of fearing an inferiority in numbers. Vandamme marched with incredible slowness. His advanced guard did not reach Point-du-Jour until 3 P.M.; (Thielemann was by this time an hour’s march beyond Gembloux!) The roads were in a very bad state, it is true, and the heavy rain that was falling made marching difficult; also the passage of the Prussians had made the roads worse; but Point-du-Jour is less than 4 miles from St Amand.
Grouchy himself went to Point-du-Jour, arriving at the same time as Vandamme’s advanced guard. Here he received his aide-de-camp, who had returned with news from Excelmans; who reported that “he was observing the enemy’s army,” and “would follow the Prussians as soon as ever they should begin to march” (Houssaye). Grouchy, instead of giving Vandamme and Gérard orders to hasten their march on Gembloux, and galloping there himself, made no effort to hurry. He accompanied Vandamme’s Corps, which still continued with extraordinary slowness; and arrived at Gembloux at seven o’clock in the evening; taking four hours to cover 5 miles. Gérard arrived there two hours later. Thus at the end of the day, Grouchy’s main body was less than 7 miles from Ligny; and he was supposed to be vigorously pressing the Prussians! He had not yet found the direction of their retreat! Compare, allowing even for the rain and the state of the roads, his rate of marching with Thielemann’s, over the same road, a few hours previously; and compare Grouchy’s subsequent retreat.
Napoleon’s first instruction to Grouchy was to concentrate all his forces at Gembloux. To enable both Corps to arrive at Gembloux together, Gérard’s should have marched off first and taken the cross-country road from Sombreffe to the old Roman road, and thence along to Gembloux. Vandamme would then have had a clear road past Point-du-Jour, undisturbed by Gérard’s troops. As it was, Gérard’s men had to traverse a road already cut up by the Prussians and Vandamme’s Corps.
Excelmans had lost every opportunity. He should not have contented himself with watching the enemy; he should have made “feints,” to cause the Prussians to disclose their intentions, or he should at least have discovered the direction of their movements. If he was too weak to attack even the rear-guard, he should have endeavoured to work round Thielemann and occupy him while Grouchy with the main body arrived. He should also have sent across to Pajol and asked him to work in towards his left so as still further to hamper Thielemann. But none of these things were done, and the Prussians were allowed to move off quietly, Excelmans merely following behind!
Even when Thielemann moved out of Gembloux at 2 P.M., it was three o’clock before Excelmans entered the village, and yet his scouts had been watching the Prussians since 9 A.M. He was content to march leisurely on to Sauvenière, a village 3 miles north of Gembloux.
Grouchy decided to halt at Gembloux for the night. Although there were still two hours of daylight left when Vandamme’s Corps reached the village, yet it was ordered to bivouac there. Grouchy afterwards stated that the roads were too bad to march on, and the rain too heavy; this is true, to a certain extent, but considering how well the Prussians had marched under the self-same conditions, and the urgency of the situation, Grouchy might have made much more progress.