Instructions soon arrived, and Berton was ordered to march on Gembloux. He therefore marched up the valley of the Orneau, a small stream running southwards to the Sambre, and arrived in front of Gembloux at 9 A.M. Here he found the Prussian outposts, and descried, on the far side of the village, the whole of Thielemann’s Corps taking their rest. Excelmans, with his remaining three brigades of cavalry, arrived before Gembloux, half an hour later, _i.e._ at 9.30 A.M. He saw that there were some 20,000 Prussians resting beyond the village, and yet he neglected to send back word to Grouchy immediately. He did not even inform Pajol of his discovery, so the latter was still wandering. Although he had 3,000 cavalry and 12 guns, Excelmans made no attempt to harass the Prussians, who, since they were resting, were obviously not ready to fight again. But his mistake lay not so much in his avoiding conflict as in his omission to send immediate news to Grouchy and Pajol. There can never be a mistake in sending back too much information to head-quarters (as far as the means of transmission allow); what is not required can there be disposed of. So much for the efforts of Excelmans and Pajol to follow up the Prussians. Grouchy, meanwhile, at 11.30 A.M., received the following written order from Napoleon:-- “Repair to Gembloux with the Cavalry Corps of Pajol and Excelmans, the Light Cavalry of the Fourth Corps, Teste’s Division, and the Third and Fourth Corps of Infantry. You will send out scouts in the direction of Namur and Maestricht, and you will pursue the enemy. Reconnoitre his march, and tell me of his movements, that I may penetrate his designs. I shall move my headquarters to Quatre-Bras, where the English still were this morning; our communication will then be direct by the Namur road. Should the enemy have evacuated Namur, write to the general in command of the Second Military Division at Charlemont, to occupy this town with a few battalions of National Guards. It is important to discover what Wellington and Blucher mean to do, and whether they meditate uniting their armies to cover Brussels and Liège by risking the fate of a battle. At all events, keep your two Infantry Corps continually together, within a mile of each other, reserving several ways of retreat; place detachments of cavalry between, so as to be able to communicate with Head-quarters.” This order contains certain very definite instructions. First, Grouchy was to concentrate all his forces at Gembloux. Secondly, he was to reconnoitre towards Namur and Maestricht, as it was very possible (according to Napoleon’s information) that the enemy had gone in those directions. Thirdly, he was to follow the tracks of the Prussians, and to try to discover what they intended to do.