The following morning the entire band set forth on their long and difficult journey across the plains. When three days had elapsed, the riders, wearied by their journey and nearly parched with thirst, were well-nigh exhausted. The supply of water which they had brought with them had proved to be inadequate. All the efforts of Kit Carson were required to keep up the courage of his followers. The heat had been intense, and the brief rest which had been given the horses and mules had not been sufficient to restore their full strength. Even the animals were dejected as they lifted their feet from the heated sands and slowly moved forward. Not a word of complaint, however, had escaped the lips of Reuben. Fearful that the objection which had been made at St. Louis against his joining a party of trappers would be repeated here, the boy had done his utmost to bear the hardships that he was compelled to endure. His lips were swollen and cracked, and the intense feeling of hunger which he had the preceding day had given place to a dull ache. His manner was thoroughly dispirited as he slowly followed his companions. The mule which he was riding had lagged behind the other animals, until Reuben was several yards in the rear of the little company. It was at this time that Carson, noting the plight of his young friend, dropped behind and waited for Reuben to approach. “Well, lad,” he said, striving to speak cheerfully, “how is it?” Reuben, almost unable to speak, shook his head as he tried to smile in response to the query of his friend. “It’s a pity, lad,” continued the guide, “but there’s no going back. We have got into a hard piece of work, but the only thing to do is to go ahead. That is the only way out, so keep up your heart and don’t give in.” Reuben nodded decidedly to show that his determination was still unbroken, and as he did so the mule he was riding suddenly lifted his head and, after he had sniffed the air, lowered it almost to the sand, and emitted several prolonged, heart-breaking, agonizing brays. The stentorian blasts were quickly answered by similar sounds from the other mules in the train. Despite the efforts of the weary men to control the beasts, they all immediately began to run, followed speedily by the horses. CHAPTER XII—A PUZZLING MESSENGER “What’s wrong? What’s the matter?” demanded Reuben excitedly of Kit Carson, who was riding by his side. “Don’t you know?” laughed the leader good-naturedly. “No, I don’t know, that’s why I asked,” replied Reuben in the disjointed words he was able to speak, while the mule which he was riding increased the speed at which he was running. “They have sniffed water.” “But I can’t see it anywhere!” “That’s likely,” replied the hunter, smiling as he spoke. He was having less difficulty than his young companion in controlling his mount.