5. We have pointed out in the text that the three principal Continental critics,—Jomini, Clausewitz and Charras,—unite in the opinion that Marshal Grouchy should have marched at daybreak for the bridge of Moustier,—covering the movement by his cavalry. What would have been the result of this manœuvre? (See Map 9.)
Let us suppose that the Prussian detachment of Ledebur, which was stationed at Mont St. Guibert to observe the movements of Marshal Grouchy’s column, had been driven out of their position, or flanked out of it (as they finally were), before six in the morning, by the French cavalry, and had been compelled to retire to the neighborhood of Wavre. The movements of the main body of Grouchy’s command might, therefore, without much difficulty, have been concealed from observation. At least this seems to be assumed by Jomini,[647] who says that Grouchy could have been at the bridge of Moustier at 10 A.M.,—and then have moved “on Wavre by Limale, pushing Exelmans’ dragoons on St. Lambert, or else have marched to Lasne himself.”
But Charras[648] thinks that the movement to Moustier would have been at once perceived by Ledebur’s cavalry, and that Grouchy would probably, on arriving at Moustier and Ottignies, have found himself in face of 40,000 men and 150 pieces of cannon, in position behind the Dyle, and that it could only have been by a very unlikely concurrence of circumstances that Grouchy could have seized these bridges before the Prussians would have been in sufficient force to oppose him.
These conclusions seem to us very strained. Grouchy had 6,000 excellent cavalry. Ledebur’s detachment consisted of two battalions of infantry, four squadrons of cavalry and two guns,—possibly 1,500 men in all.[649] A movement on Corbaix would have compelled him to fall back to La Baraque as surely at five in the morning as at one in the afternoon, when, as we have seen, it had this effect. Certainly, Ledebur could have been got out of the way, and could only have reported that the French were very active, and were manœuvring apparently on Wavre by way of Corbaix and La Baraque. We see no reason to doubt that Jomini is perfectly correct in supposing that the column of Marshal Grouchy, with the exception of one of his cavalry divisions, say, that of Pajol, supported, perhaps, by the infantry division of Teste, could have crossed the bridges of Moustier and Ottignies, without any molestation whatever, by or soon after 10 A.M., and that they might have been well on their way towards Lasne and St. Lambert before the Prussians were aware what they were about.
In speculations of this kind, it is very easy, of course, to omit by accident some of the data of the problem. But when it is remembered that the principal subject which the Prussians were contemplating that morning was not the movements of the 12,000 or 15,000 men, who were (as they supposed)[650] all the troops which Napoleon had detached against them, but the very serious question whether the whole army, or three-fourths of it, should march across the country to attack Napoleon and succor Wellington, we can hardly believe that any reports which Ledebur could have brought in would have brought 40,000 men to the bridges of Moustier and Ottignies by 10 or 10.30 A.M.
It seems to us, then, altogether probable that Marshal Grouchy could have crossed the Dyle at Moustier and Ottignies with the bulk of his forces before 11 A.M.[651]
At this hour, only “the advanced guard of Bülow’s corps had * * * reached St. Lambert. The 16th, and then the 13th, brigade arrived much later, and the 14th brigade, which formed the rear-guard was a long way behind.”[652] At this hour the Ist, IId and IIId Corps were still in and about Wavre. It would have been at this moment, when the IVth Corps was thus strung out, toiling through the bad roads, that Grouchy would have made his appearance, and have commenced his march from Moustier and Ottignies to Lasne and St. Lambert. Can it be believed that he would not have stopped Bülow? What else could Bülow have done but halt, and concentrate his command, and await the reinforcements which were expected from Wavre? But this would have involved him in an engagement with Grouchy’s force, from which he could be released only by the arrival of those reinforcements. When would they have arrived? (See Map 10.)
If Grouchy’s movement on Moustier had not been observed and promptly reported to Blücher,—which is the assumption on which we are proceeding, as being on the whole the most probable,—there is no reason to suppose that the Ist and IId Prussian Corps would have moved out of Wavre earlier than they did,—that is, about noon.[653] The IId Corps followed the IVth, and would of course have become engaged with Grouchy. The IIId would in time very likely have followed the IId; but it probably would not have left Wavre till much later. These three corps would have been Grouchy’s opponents; they would have outnumbered him considerably, and would, no doubt, ultimately have worsted him. But he probably would have prevented any portion of their troops from attacking the main army under Napoleon.