'It is just as I knew it was,' said Kanker, throwing down the book. 'Another of your absurd hallucinations. You dream about things until you think they are real. You had much better do as I do--wear spectacles, make up your mind that everything is a lie, and trust to your fingers. By doing that you might, in the course of time, come to know something. Look here, I'll tell you what I'll do. I'll make an exchange with you. It isn't a fair exchange, for what I give you is worth a great deal, and what you give me is worth nothing. You give me your book, and I'll give you mine.' 'What is your book?' Oscar asked. 'An arithmetic, to be sure!' replied Kanker, pulling it out of his pocket. 'See, here is the multiplication table. And here are addition, subtraction, multiplication, and division. And here are vulgar fractions. And here are examples. And here is the Rule of Three. That's what I call a book worth having.' 'But if you think my book is not worth having, why do you want it?' 'To make a fire to warm myself with,' Kanker replied. 'If you are cold, will not the sun warm you?' asked Oscar. 'No one has been able to prove that there is any warmth in the sun,' said Kanker. 'It only seems to be warm. But I know that a fire is warm, because I can burn my fingers in it.' 'But if the sun feels warm, is not that as good as if it were really warm?' 'For you it may be,' answered Kanker, 'but not for me. I care only for truth, and I don't choose to be warmed by anything I don't believe in. That is the reason I carry a sun-umbrella. Well, will you let me have your book?' 'It is no more use to me,' said Oscar, gloomily. 'I do not care whether you take it or not, or what becomes of it.' 'You will find my arithmetic much more useful,' returned Kanker. 'Come outside and see me make my fire.' But Oscar turned sullenly away. Kanker went outside the cottage, with the book in his arms. After a moment, Oscar could not help going to the window to see what was being done.