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]