"Yes," came the immediate reply. "Then let go!" Crash! Both guns let go almost as one, and the feeding herd was thrown into a wild panic. CHAPTER VIII CHARGED BY A BULL THE first thing the boys noticed was the fact that two of the great beasts had gone down in answer to their shots. The camp was likely to have an abundance of fresh meat that night at least. [Illustration: "'RUN FOR THE TREES, ROGER!' SHOUTED DICK"] Then another thing drew their attention. "Look at the bull!" cried Roger suddenly, as he noticed that the guardian of the herd was plunging in their direction as though bent on seeking a prompt revenge for the loss of his charges. The predicament of the boys was not at all to their liking. Without a bullet in their guns, and with a maddened bull bearing down upon them at full speed, unless they made a rapid retreat to the timber they were in danger of being gored and trampled by the horns and hoofs of the beast. "Run for the trees, Roger!" shouted Dick, as he himself turned and made for the timber. Fortunately they were not far from shelter. Roger had before been, inclined to lament the fact that the mass of dead grass did not allow them to creep closer to the game, but he changed his mind now, when every yard counted against them. Once Roger caught his foot somehow, and fell flat. Dick seemed to know it, although his back was turned to his chum at the time, for he instantly stopped in his headlong rush and whirled around. It was his intention to stand by his comrade, come what would, to divert, if necessary, the attention of the charging animal until such time as Roger could gain his feet. It turned out that the sacrifice was not needed, for, nimble as a cat, Roger gained his feet like a flash, and, putting on a fresh spurt, succeeded in reaching the outermost trees as soon as Dick. They were none too soon. The galloping buffalo was close at their heels. Had the friendly timber been ten paces further off there might have been a different story to tell. Each boy chose a tree behind which he tried to shield himself. The bull rushed past, but immediately came to a halt, turned and started to chase Roger around the tree which he had taken for a guard. "Faster, Roger, faster!" called Dick, alarmed lest the animal overtake the boy. This shout caused the bull to take notice of his other enemy, and he plunged directly toward Dick, who was compelled to make circles around his shelter at a lively pace, in order to keep from being impaled on those wicked-looking short black horns. Having the inside track the boy of course was given an advantage, but it seemed as though that tough old monster would never tire. He kept on circling the tree, making savage prods at the legs of his intended quarry whenever Dick lagged a little, or, slipping, fell back a step or so.