"That tree was sounder than the one where the bear had his den," he kept muttering to himself as he hurried along over the blackened ground in the direction where he believed he must find the hollow oak given over to Sandy; "and after it was all over he could come out much easier than I did. But why have I not heard his signal call? Would he not follow after the fire, seeking some sign of me?" Bob had just come through a very extraordinary adventure, for some time his life had actually hung in the balance; but he quickly forgot all about this in the new anxiety about his brother. More than once he had to cast about him to be sure that he was heading the right way. Somehow, since the fire had burned over the ground, eating up the masses of dead leaves and other inflammable growths, things did not look the same as before. "But the wind came down from the north," he kept saying, as he pushed doggedly on over the smoking ground; "and that is the way I'm going back now. Only, I seem to be in a new part of the forest, things look so different. But hold on, Bob, there's that cross formed by two trees that fell toward each other. I remember that plainly, and it was just after I left Sandy, too." Now he was sure that the hollow tree must be somewhere close by. He raised his voice, and called the name of his brother. "Sandy! Hello! where are you?" Through the desolate forest, with its blackened carpet, the sound of his voice came back to mock him. Nothing else responded to his hail. Louder than before he shouted, but there was no answering call. Bob again felt that terrible chill in the region of his heart. A brief time before, and he had been apparently burning up; now he was shivering. "There it is!" he suddenly cried, as he happened to let his wandering gaze fall upon a tree that seemed to have a gap in its side. He hurried forward. Even as he advanced other familiar things greeted him, so that his last lingering doubt vanished. "It's the tree, surely," he muttered, straining his eyes to see within, and almost holding his very breath lest he discover a motionless figure in the cavity. But it was empty! At least Sandy had not been smothered by the dense smoke; he must have left his retreat. "Oh! I hope he stayed here until the worst was over!" was the cry that burst from the boy, as he stood there, staring into the empty _cache_, which he had intended to be a means of life-saving to his brother. He turned and looked around. There did not seem to be a living thing in sight. Animals and birds had all been driven away by the fire, which was doubtless still rushing through the woods far to the south. Was it worth while to call out again? Surely if Sandy had been within half a mile of him he must have heard that last shout! Puzzled, and sorely distressed, Bob hardly knew what to do. He even looked again into the hollow tree, as though in that way he might receive an answer to his question as to what had become of his brother. And he did.