It was rare, particularly in the wooded districts of the country of the cave men, for a boy of nine to go a mile from home alone. There was danger lurking in every rod and rood, and, naturally, such a boy would not be versed in all woodcraft, nor have the necessary strength of arm for a long arboreal journey, swinging himself along beneath the intermingling branches of close-standing trees. So this departure was, for Ab, a venture something out of the common. But he was strong for his age, and traversed rapidly a considerable distance through the treetops in the direction of what he saw. Once or twice, though, there came exigencies of leaping and grasping aloft to which he felt himself unequal, and then, plucky boy as he was, he slid down the bole of the tree and, looking about cautiously, made a dash across some little glade and climbed again. He had traversed little more than half the distance toward the object he sought when his sharp ears caught the sound of rustling leaves ahead of him. He slipped behind the trunk of the tree into whose top he was clambering and then, reaching out his head, peered forward warily. As he thus ensconced himself, the sound he had heard ceased suddenly. It was odd. The boy was perplexed and somewhat anxious. He could but peer and peer and remain absolutely quiet. At last his searching watchfulness was rewarded. He saw a brown protuberance on the side of a great tree, above where the branches began, not twoscore yards distant from him, and that brown protuberance moved slightly. It was evident that the protuberance was watching him as he was watching it. He realized what it meant. There was another boy there! He was not particularly afraid of another boy and at once came out of hiding. The other boy came calmly into view as well. They sat there, looking at each other, each at ease upon a great branch, each with an arm sustaining himself, each with his little brown legs dangling carelessly, and each gazing upon the other with bright eyes evincing alike watchfulness and curiosity and some suspicion. So they sat, perched easily, these excellent young, monkeyish boys of the time, each waiting for the other to begin the conversation, just as two boys wait when they thus meet today. Their talk would not perhaps be intelligible to any professor of languages in all the present world, but it was a language, however limited its vocabulary, which sufficed for the needs of the men and women and children of the cave time. It was Ab who first broke the silence: "Who are you?" he said. "I am Oak," responded the other boy. "Who are you?" "Me? Oh, I am Ab." "Where do you come from?" "From the cave by the beeches; and where do you come from?" "I come from the cave where the river turns, and I am not afraid of you." "I am not afraid of you, either," said Ab. "Let us climb down and get upon that big rock and throw stones at things in the water," said Oak. "All right," said Ab.