XVI.--Though Caesar could not perceive the retreat of the enemy for the intervention of the fire, yet, suspecting that they had adopted that method to favour their escape, he made his legions advance, and sent a party of horse to pursue them; but, apprehensive of an ambuscade, and that the enemy might remain in the same place and endeavour to draw our men into a disadvantageous situation, he advances himself but slowly. The horse, being afraid to venture into the smoke and dense line of flame, and those who were bold enough to attempt it being scarcely able to see their horses' heads, gave the enemy free liberty to retreat, through fear of an ambuscade. Thus, by a flight, full at once of cowardice and address, they advanced without any loss about ten miles, and encamped in a very strong position. From which, laying numerous ambuscades, both of horse and foot, they did considerable damage to the Roman foragers. XVII.--After this had happened several times, Caesar discovered, from a certain prisoner, that Correus, the general of the Bellovaci, had selected six thousand of his bravest foot and a thousand horse, with which he designed to lie in ambush in a place to which he suspected the Romans would send to look for forage, on account of the abundance of corn and grass. Upon receiving information of their design Caesar drew out more legions than he usually did, and sent forward his cavalry as usual, to protect the foragers. With these he intermixed a guard of light infantry, and himself advanced with the legions as fast as he could. XVIII.--The Gauls, placed in ambush, had chosen for the seat of action a level piece of bound, not more than a mile in extent, enclosed on every side by a thick wood or a very deep river, as by a toil, and this they surrounded. Our men, apprised of the enemy's design, marched in good order to the ground, ready both in heart and hand to give battle, and willing to hazard any engagement when the legions were at their back. On their approach, as Correus supposed that he had got an opportunity of effecting his purpose, he at first shows himself with a small party and attacks the foremost troops. Our men resolutely stood the charge, and did not crowd together in one place, as commonly happens from surprise in engagements between the horse, whose numbers prove injurious to themselves.