Every ounce of strength each boy possessed was required for the effort. Occasionally the guide shouted his direction first to one boy and then to another and then to both alike. Neither Fred nor John, however gave much heed to their advisor nor indeed was it possible for them to hear what he said. The sound of the noisy water filled their ears, the peril of the projecting rocks continued to face them and a glance at the dark colored stream below was sufficient to warn them of dangers to be avoided there. Fred, who, as has been said, was paddling from the bow turned for a moment to glance back at John. At that moment, however, the heavy boat suddenly struck an unseen rock. The force of the current was sufficient to drive the boat safely over the place of peril, but Fred as he had nearly lost his balance glanced again behind and to his horror he saw the long legs of John disappearing over the side of the boat. CHAPTER X A RATTLER Meanwhile the other party which had started for Thorn's Gulch was also having its own experiences no less thrilling than the mishap which had befallen John. Zeke was the leader of the trio while George had taken Pete's place as rear guard. Steadily climbing the way which previously they had used as a path, stopping frequently for rest, for their breathing was somewhat more difficult in the high altitude than on the lower levels, they at last succeeded in gaining the crest of the canyon. Zeke then led the way across the table-land, at times moving far from the border and then again approaching almost within sight of the great canyon. The Canyon of Arizona extends for hundreds of miles, becoming vast and wide in what is commonly known as the Grand Canyon. It winds through the country at times visible and sometimes concealed from sight by intervening cliffs or trees. Before the noon-hour arrived the party halted, seeking the shelter of a small cleft in the rim where they were able to start a fire and cook some of the food they had brought with them. The heat was so intense that Zeke commanded the expedition to wait until late in the afternoon before the journey was resumed. Although neither George nor Grant acknowledged that he was tired, both Go Ahead Boys were entirely willing to heed the advice that was given them. Late in the afternoon the three explorers again resumed their journey. A brief halt for supper was made, but soon afterward the boys once more were following Zeke as he led the way in the moonlight. The air was cool now and although the altitude was still high the boys found less difficulty in breathing. In a sheltered spot well known to Zeke a camp was pitched for the night and soon after they had cast themselves upon their blankets all three were soundly sleeping.