When the two forces came within distance, the light-armed troops in front of the two armies closed with each other. In this part of the battle the Romans were in many respects at a disadvantage, while the Carthaginians had everything in their favour. For the Roman spearmen had been on hard service ever since daybreak, and had expended most of their weapons in the engagement with the Numidians, while those weapons which were left had become useless from being long wet. Nor were the cavalry, or indeed the whole army, any better off in these respects. The case of the Carthaginians was exactly the reverse: they had come on the field perfectly sound and fresh, and were ready and eager for every service required of them. As soon, therefore, as their advanced guard had retired again within their lines, and the heavy-armed soldiers were engaged, the cavalry on the two wings of the Carthaginian army at once charged the enemy with all the effect of superiority in numbers, and in the condition both of men and horses secured by their freshness when they started. The Roman cavalry on the contrary retreated: and the flanks of the line being thus left unprotected, the Carthaginian spearmen and the main body of the Numidians, passing their own advanced guard, charged the Roman flanks: and, by the damage which they did them, prevented them from keeping up the fight with the troops on their front. The heavy-armed soldiers, however, who were in the front rank of both armies, and in the centre of that, maintained an obstinate and equal fight for a considerable time.