Don was well aware of that fact. The roof was made of logs as heavy as they could manage with their united strength, and there were other logs placed upon it in such a position that when the roof fell, their weight would assist in holding it down. All these precautions were necessary, for a bear can exert tremendous strength if he once makes up his mind to do it; and David had repeatedly declared that if they should chance to capture an animal as large as the one that had been killed on that very island years before, the pen would not prove half strong enough to hold him. But it was quite strong enough to hold Don if he got into it, and the only way his companions could have released him would have been by cutting the roof in pieces with their axes. The work was all done now, and the boys were ready to start for home. While Bert and David were gathering up the tools and stowing them away in the canoe, Don scattered a few ears of corn around, so that the bear would be sure to find them the next time he visited the island, and threw a dozen or so more into the trap close about the trigger. The rest of the corn he hung up out of reach on a sapling which he knew was too small for the bear to climb. Assisted by the current the canoe made good time down the bayou. Bert and David lay back in the stern-sheets and said they were tired, while Don, who was seated at the oars, declared that his day's work had relieved his stiff joints, and that he began to feel like himself again. He was fresh enough to assist in building another trap without an hour's rest; and in order to work off a little of his surplus energy, he thought when he reached home he would take a turn through the fields in company with his pointer, and see if he could bag quails enough for his next morning's breakfast. Bert said he would go with him, for he wanted to see the pointer work. In about three quarters of an hour the canoe entered the lake and drew up to the bank in front of Godfrey's cabin. David sprang out, and after placing his gun upon the bench in front of the door, went behind the building to unchain the pointer. He was gone a long time--so long that Don and Bert, who were sitting in the canoe waiting for him, began to grow impatient--and when he came back he did not bring the pointer with him. He brought instead a chain and a collar. His face told the brothers that he had made a most unwelcome discovery. "Where's the dog?" asked Bert. "I don't know," answered David, looking up and down the road. "He must have slipped the collar over his head and gone off; but I never knew him to do it before." "Well, you needn't look so sober about it," said Don. "He isn't far away. I'll warrant I can bring him back."