The well-trained horses, accustomed to their masters firing from their backs, stood as steady as if carved in stone, their heads turned inquiringly toward the yelling throng of horsemen who were approaching. Mr. Hardy and the boys had both dismounted, so that the horses were between them and the Indians, the saddles serving as rests for their firearms. "Five hundred yards, Charley?" his father asked quietly. "A little over, papa; nearly six, I should say." Mr. Hardy waited another ten seconds, and then his rifle cracked; and a yell of astonishment and rage broke from the Indians, as one of their chiefs, conspicuous from an old dragoon helmet, taken probably in some skirmish with the soldiers, fell from his horse. "Hurrah!" Charley cried. "Shall we fire now, papa?" "No, Charley," Mr. Hardy said as he reloaded his rifle; "wait till they are four hundred yards off, then fire slowly. Count ten between each shot, and take as steady an aim as possible. Now! Well done, two more of the scoundrels down. Steady, Hubert, you missed that time: there, that's better." The Indians yelled with rage and astonishment as man after man dropped before the steady and, to them, mysterious fire which was kept up upon them. Still they did not abate the rapidity of their charge. "Done, papa," Charley said as the two boys simultaneously fired their last shot, when the leading Indians were about two hundred and fifty yards distant. "Change your chambers and mount," Mr. Hardy said as he again took aim with his rifle. The enemy was not more than a hundred and fifty yards distant, when they leaped into their saddles and started at a gallop. "Steady, boys, keep your horses well in hand. Never mind their balls; they could no more hit a man at this distance from the back of a horse than they could fly. There is no chance of their catching us; there won't be many horses faster than ours, and ours are a good deal fresher. Keep a good lookout for holes." Both pursuers and pursued were now going over the ground at a tremendous pace. The Indians had ceased firing, for most of those who had guns had discharged them as Mr. Hardy and his sons had mounted, and it was impossible to load at the speed at which they were going. During the first mile of the chase Mr. Hardy had looked round several times, and had said each time, "We are holding our own, boys; they are a good hundred yards behind; keep your horses in hand." At the end of another mile his face brightened as he looked round. "All right, boys, they are tailing off fast. Three-quarters of them have stopped already. There are not above a score of the best mounted anywhere near us. Another mile and we will give them a lesson." The mile was soon traversed, and Mr. Hardy saw that only about twelve Indians had maintained their distance. [Illustration: ONSET OF THE INDIANS.]