It was with a feeling of dread that he rode back through the jungle, expecting every minute to feel the impact of a bullet. But he emerged safely on the other side without any message from the hidden enemies. Darkness fell soon after he left the jungle, but he merely let slack the reins and trusted to his animal's instinct to find the way home. Soon he spied the lights of the machine in the distance, and a half hour later he dismounted at the camp, aching and sore in every muscle of his body, and discouraged over his fruitless trip. CHAPTER XV. THE FIRST BLOW. "THIS mystery business just seems to get thicker and thicker," Captain Westfield remarked, when Charley had finished relating his experience of the day. "Smokeless powder and Maxim silencers are no ways common out in these woods." "It startled me for a minute," Charley admitted. "No smoke, no sound--just the whine of the bullets coming out of that frightful jungle got me for a while. I did not know which way to go, forward or back. I don't know whether they meant to kill me or not, but they pretty nearly scared me to death." "Did you meet a little man with a spade-like beard?" Walter asked. "No," said his chum. "Was there one here?" "Yes. He was on horseback, and came from the direction of Jupiter. The bridge builders stopped him and sent in word to me. I went out and escorted him by the machine. He said his name was Jones, and that he had a young orange grove out near Indiantown." "You did not let him go near the machine, did you?" Charley inquired anxiously. "I did not," said his chum emphatically. "He wanted to stop and chat with the engineers, but I told him we did not permit anyone around the machine but our own men, and he rode on." "Funny," Charley observed. "I did not meet him. He must have turned off into the woods somewhere. I wish I had got a glimpse of him. I have an idea that he is the boss those convicts were talking about." "He was a mild-mannered, kind of timid-looking, little man," Walter objected. "He did not look as though he would hurt a fly." "Mild-appearing men are sometimes the worst of all," Charley observed, as he stretched out on his cot. "Gee! but I am tired enough for a twenty-four hours' sleep." But, tired as he was, the lad could not go to sleep. His active brain kept turning over every event that had occurred, in a vain search for a clew as to who their enemies were, and what was their purpose. That they would resort to desperate measures, if necessary, he had not the slightest doubt. The placing of the dynamite under the machine, the presence of the convicts, and the shots in the jungle, proved that. It must be a powerful motive that would induce men to go so far. For all his knowledge of the state and its people, the lad could not think of anything in this wild, remote country that would tempt men to risk the hangman's rope.