"We will not get that until the middle of next month," his chum said gloomily. "If we are forced to quit the job before then we will get nothing. The county will keep it for failure to carry out our contract. We have just simply got to keep the machine working, that's all." When the boys arrived at camp, Charley went at once to the hospital tent, where he found both sick men slightly improved. He left four quinine tablets with each, with directions to take one every two hours. To Chris he gave instructions to prepare some rich broth and dry toast for the invalids. This done, the two lads turned in and slept soundly until well along in the afternoon. They found the Captain had not been idle while they rested. With his graders he had thrown up mounds of dirt and roots every fifty feet circling the camp. "Good!" approved Charley, as he viewed the old sailor's work. "When we get behind those we will be fairly safe from bullets. I wish those trees out there were out of the way. They give the enemy too much protection." "There are only about a dozen of them big enough to give any protection," Walter observed. "Why not blow them up with dynamite?" The suggestion was a good one and they immediately set about carrying it out. Assisted by the Captain with his graders, they dug holes under the trees' roots and placing several sticks of dynamite under each, thus exploded them with a fuse and cap. The powerful explosive blew the big trees clear out of the ground and in some cases many feet above ground before they fell. "That's better," said Charley, with satisfaction when the job was completed. "We can make still another improvement," Walter suggested. "Why not set fire to the roots? They are pitchy enough to burn good and the fires will show up any one trying to approach the camp." The idea was so feasible that the lads carried it out at once, and by the time night fell a bright glowing ring of fires surrounded the camp. "I don't believe they will bother us to-night with all those fires going, but we'll keep watch just the same," Charley said. "We cannot be too careful." The camp was not molested during the night, but about the middle of the night there came explosions at regular intervals from the direction of Indiantown. Charley chuckled. "They are shutting the stable door after the horse is stolen," he remarked. "They are blowing up the bridges between here and Indiantown." "I expected that would be their next move. That's why I was in such a hurry to get the provisions from the Indians." "But the blowing up of the bridges ahead of us will stop the machine," Walter said. "No, it will only delay us a little," his chum replied. "It's easily remedied. When the machine gets to a blown-up bridge it will simply face around and fill up the gap with mud and sand, and after it has passed over it will dig out the gap again and our bridgemen will put in a new bridge, which they would have to do anyway."