There is a coarseness of speech which strains the credulity of children. Their innocence is spared because adult anger is quite unlike the brief, quickly-aroused belligerency which results in blackened eyes, and bruised knuckles. Listening, Peter and Susan both knew that Mr. Caxton's anger was a thing peculiar to himself. It could only have been brought forth piping hot from the kindling of great, smouldering fires deep inside him. He could be heard shouting and cursing in the darkness for a full minute before he came striding into the shack. "You little devils!" he shouted. "Next time you scream like that you'll wish you hadn't. Oh, how you'll wish you hadn't! How can a man get any rest when he can't hear himself think?" "It wasn't me," Susan said. "It was Peter. If you saw what we saw you'd scream too, Mr. Caxton." "Now wait a minute," Mr. Caxton said. "Stop right there. Before I listen to any of that you may as well know that screaming is a luxury you can't afford." Susan refused to wait. "Peter saw what it was made the clawmarks," she said, defiantly. "I saw it too." Mr. Caxton stood very still, looking at her. "Likely enough," he said, with derisive malice. "The clawmarks couldn't just stand alone. You have to work over a gnat to make it bring forth a mountain." "It's true, Mr. Caxton," Peter corroborated. "We both saw it. It was all covered with feathers." "One moment, boy!" Mr. Caxton rasped. "Exactly where was it standing when you saw it?" "In the doorway," Peter said. "In the doorway. How interesting. There's no animal life at all on Mars. But _you_ saw a bird. How tall was it, boy?" "Much taller than you are, Mr. Caxton!" Susan said, quickly. Mr. Caxton bent, and gripped Peter's arm. "I asked Peter," he said, shaking him. "Speak up, boy. Is there something wrong with your tongue?" "It was big, Mr. Caxton," Tommy managed. "It had four toes. Two in front, and two in back." "And a long, curving bill, I suppose." "I don't know, Mr. Caxton." "You've seen pictures of birds--Earth birds. Did you ever see a bird without a bill?" "No, Mr. Caxton. But it was dark. It just stood in the door, and looked at me." In the human mind deliberate, calculated cruelty can wear many masks. Its range is infinite, its devious twistings and turnings often subtle beyond belief. Mr. Caxton could have slapped Peter's face, or so terrified him by shaking him that he would have thrown himself down, and given way to a wild, uncontrollable fit of sobbing. But Mr. Caxton had a better, and far more sagacious idea. The boy fancies himself an explorer. Teach him a lesson he'll never forget. Prove to him that his knowledge of the natural sciences would disgrace a four-year-old--no, an infant in swaddling clothes. "All right, Peter," Mr. Caxton said. "Suppose we take a look at the planet Mars. It's the planet of your birth, remember. A boy with real intelligence should know a great deal about the planet of his birth, shouldn't he?"