Hannibal's plan was sufficiently simple. He was well aware--for what we should now call his "intelligence department" seems to have been admirably managed[19]--of Sempronius's eagerness for battle. In the country that lay between the two camps was a spot which seemed admirably suited for an ambush; the bed of a stream, closed in on either side by steep banks, and enclosing a considerable space of level ground, thickly covered with bush. Here he put his brother Mago with a picked force of 2,000 men, composed of equal numbers of cavalry and infantry. "You have an enemy," he said in dismissing them, "who is blind to these stratagems of war." How familiar the words have been made by recent experiences of our own! These arrangements made, Hannibal sent his Numidian cavalry at dawn the next day with instructions to ride up to the Roman camp, to pour a shower of missiles upon the sentries, and, if possible, to provoke an engagement. Sempronius was, he knew, eager to fight. This insulting demonstration would stir the temper of the men in such a way that they would obey with enthusiasm a command to advance. The device was completely successful. Sempronius led forth his men in hot haste after the Numidians, who retreated in apparent disorder. The Romans, thus hurriedly summoned, had not had a meal; their horses had not been fed; and they suffered from cold as well as from hunger. It was a snowy day in November, and the region, the marshy, low-lying ground between the Alps and the Apennines, had an inclement climate. More than this, they had to cross the river, whose waters, swollen by the autumn rains, and now breast high, struck a piercing cold into their limbs. When they emerged on the other side of the stream they could scarcely grasp their weapons. Hannibal's men were in very different case when they were led forth to encounter the enemy, warmed by fires in their tents, and strengthened by a leisurely meal. The order of battle was this. The slingers were in front; on either wing the cavalry and the elephants; in the centre the heavy-armed infantry. The total number is given by Polybius at about forty thousand. Half of these were infantry, Spaniards, Africans, and Gauls, these last representing the addition which Hannibal had been able to make to the army of the Alps. The cavalry numbered more than ten thousand. Here also Gauls appear as "Celtic allies." Of the slingers there were eight thousand. The Roman force was almost exactly equal, but differently made up. It had but four thousand cavalry, as against ten thousand. Of the infantry, sixteen thousand were Romans, and twenty thousand auxiliaries.