"I’m not sure, Bill," replied Middleton, "but it must signify some movement. The Mexicans, like many other people, love color and parade and sound, but they would scarcely be indulging in such things at midnight just for their own sakes. It is some plan. Santa Anna is a man of great energy and initiative. But we must discover what it is. That is what we came for." The advance was renewed, although they went slowly, guarding as well as they could against the least possible sound from their horses. They were now so near that they could see figures passing before the fires, and the dark outline of tents. They also heard the hum of many voices, the tread of hoofs by hundreds, and the jingling of many, spurs and bridle bits. Phil watched almost breathless, and the desert wind still blew on his face, stirring him with its fine, impalpable powder, and adding new fire to the fire that already burned in his veins. And Phil saw that Middleton shared in this excited interest. The officer’s gloved hand on his bridle rein quivered with eagerness. "Yet a little nearer, my lads," he whispered. "We must risk everything to find out what Santa Anna is intending at so late an hour." Screened by a narrow thicket of strange, cactuslike plants, they rode so close that they could see between the leaves and thorns directly into the camp. Here they sat on motionless horses, but Phil heard a deep "Ah!" pass between Middleton’s closed teeth. The boy himself had experience and judgment enough to know now what was going forward. All this jingling of bits and spurs meant the gathering of the Mexican cavalry. The Mexican camp fires burned along a front that seemed interminable, and also scores of torches were held aloft to guide in the work that was now being done. Phil saw the Mexican horsemen wheel out by hundreds, until there was a great compact body of perhaps two thousand men, gaudily dressed, well mounted, and riding splendidly. Many carried rifles or muskets, but there were at least a thousand lancers, the blades of their long weapons gleaming in the firelight. Officers in gorgeous uniforms were at their head. Presently the trumpet blew again, and the great force of cavalry under General Minon began to move. "An advance at midnight," breathed Middleton, but Phil heard him. "And there go infantry behind them. It is an attack in force. I have it! I have it! They are going toward Agua Neva. Santa Anna thinks that our whole army is there, and probably he believes he can get in our rear and cut us off. Then he’ll compress us between his vast numbers as if we were in the jaws of a vise." Then he added, in a slightly louder tone: "Come, my lads, we ride to Agua Neva, but we must be as careful as ever. We know now what our task is, and we will do it."