With great caution the two boys advanced to the point agreed upon. Then they rode out to where the lassoes could be used freely. In the meantime the mustang was grazing peacefully, utterly unconscious of their presence in the vicinity. But now, as they drew still closer, he stopped cropping the grass and raised his head as if to listen. "Throw!" cried Dan, and the lasso left Ralph's hand with a whizzing sound. A few seconds later Dan made his own cast. As luck would have it, both landed over the mustang's head, but while Dan's was drawn tight with great quickness, Ralph's remained loose, so that in a twinkle the mustang shook it off, and then of course the line tightened around Dan's lariat instead. [Illustration: "'HOLD BACK!' YELLED DAN."] "Hold back!" yelled Dan, as he saw Ralph sit bewildered in the saddle. "Run off to the other side!" The younger Radbury attempted to obey, but as quick as a flash the mustang turned and rushed forward, bringing the lasso around Ralph's own steed. Then came a snap of the lariat, and Ralph went down, with the mustang on top of him. All this took scarcely more time than to describe it, and now Dan found himself holding the white mustang alone, with Ralph's lariat end entangled in his own. Then off went the wild animal, kicking and plunging in a desperate fashion, which even the tightened leather about his neck did not appear to hinder. His course was straight for the timber, and he went on dragging Dan's pony after him. It is true the pony might have held back, but he was not well broken for such a purpose, having participated in but few round-ups. "Look out! You'll be killed!" yelled Ralph, as he struggled to get out from under his pony. The wind had been knocked out of him, but otherwise he was uninjured. Dan scarcely heard him, so busy was he trying to bring the white mustang to a halt. Soon he disappeared into the timber, and then Ralph arose, mounted the pony once more, and came after him. The white mustang did not enter the forest far before the lariat around his neck began to hurt him. He tried to circle around several trees, and thereby cut himself short to such an extent that he was in great danger of choking to death. "Hold my pony!" shouted Dan to Ralph, and slipped to the ground. The free end of the lariat was passed around a tree and tied, and Dan sprang forward toward the white mustang, who was now acting as if ready to give up the battle. "Easy now, easy," said Dan, soothingly, and watching his chance, he hopped up on the mustang's back. Immediately the animal bucked and plunged, trying his best to throw his rider. The lariat was depriving him of his wind, and of a sudden he stopped short and trembled, as if about to fall.