Now at 4 o’clock only two brigades[605] of Bülow’s (IVth) Corps had passed through Lasne. They, with the artillery and cavalry which accompanied them, were at that moment resting and reforming in the Wood of Paris,[606] a little wood just west of the town of Lasne, after an exhausting march.[607] The other two brigades were between St. Lambert and Lasne. The IId Corps was stretched along the road between Wavre and St. Lambert. It had not yet reached the latter place.[608] The Ist Corps was a mile and a half from Ohain, on the northerly road. The IIId Corps was in and about Wavre. (See Map 11.) If, then, Marshal Grouchy had succeeded in the operation of crossing the Dyle at the four bridges or any of them while Thielemann’s Corps was detained in Wavre by Pajol and Teste, and if he had boldly advanced towards Lasne and St. Lambert, he would certainly have arrested the march of Bülow and Pirch I. Although the Prussians would have been superior in numbers, they yet would have been compelled to halt and form line of battle on observing the advance of Grouchy’s 30,000 men. The chances are that Grouchy would ultimately have been forced to retire; he could hardly have been a match for the 50,000 men opposed to him; and his retreat could at any time have been precipitated by an attack on his right flank by Thielemann, if that officer had felt himself at liberty to leave Wavre. Yet these operations would without question have consumed the rest of the afternoon; it would almost certainly have been impossible for the corps of Bülow and Pirch I. to have attacked the French at Planchenoit that day. Zieten certainly might have pursued his march unmolested if he had thought it wise to do so. How these movements would have affected the result of the battle of Waterloo, we will consider when we come to the account of the battle. All we want to show at this stage of the narrative is, that, had Gérard’s counsel been taken, Marshal Grouchy’s command might have been across the Dyle at Moustier and the other bridges by 4 P.M., and that at that moment the van of the IVth Corps had only just passed through Lasne. It is time that we returned to the Prussians. Bülow, whose corps (the IVth) had not been engaged at Ligny, was ordered to march at daybreak from Dion-le-Mont, where he had passed the night, for St. Lambert, with the view of attacking the French right.[609] He had a long distance to go, and was, moreover, detained by a fire which broke out in the streets of Wavre, and his main body did not reach St. Lambert till noon.[610] Here there was a long halt.[611] The IId Corps was to follow the IVth, but for some reason or other it did not begin to leave Wavre till nearly noon,[612] and it was not until 4 P.M. that the whole corps had got through the town and had taken the road for St. Lambert.[613]