“Oh, uncle!” answered Harry, “in the first place, the air you blow bubbles with mostly comes in at the nose and goes out at the mouth, without having been breathed at all. Then it is warmed by the mouth, and warmth, you know, makes a measure of air get larger, and so lighter in proportion. A soap-bubble rises for the same reason that a fire-balloon rises—that is, because the air inside of it has been heated, and weighs less than the same sized bubbleful of cold air.” “What, hot breath does!” said Mr. Bagges. “Well, now, it’s a curious thing, when you come to think of it, that the breath should be hot—indeed, the warmth of the body generally seems a puzzle. It is wonderful, too, how the bodily heat can be kept up so long as it is. Here, now, is this tumbler of hot grog—a mixture of boiling water, and what d’ye call it, you scientific geniuses?” “Alcohol, uncle.” “Alcohol—well—or, as we used to say, brandy. Now, if I leave this tumbler of brandy-and-water alone—” “_If_ you do, uncle,” interposed his nephew, archly. “Get along, you idle rogue! If I let that tumbler stand there, in a few minutes the brandy-and-water—eh?—I beg pardon—the alcohol-and-water—gets cold. Now, why—why the deuce—if the brand—the alcohol-and-water cools; why—how—how is it we don’t cool in the same way, I want to know? eh?” demanded Mr. Bagges, with the air of a man who feels satisfied that he has propounded a “regular poser.” “Why,” replied Harry, “for the same reason that the room keeps warm so long as there is a fire in the grate.” “You don’t mean to say that I have a fire in my body?” “I do, though.” “Eh, now? That’s good,” said Mr. Bagges. “That reminds me of the man in love crying, ‘Fire! fire!’ and the lady said, ‘Where, where?’ And he called out, ‘Here! here!’ with his hand upon his heart. Eh?—but now I think of it—you said, the other day, that breathing was a sort of burning. Do you mean to tell me that I—eh?—have fire, fire, as the lover said, here, here—in short, that my chest is a grate or an Arnott’s stove?” “Not exactly so, uncle. But I do mean to tell you that you have a sort of fire burning partly in your chest; but also, more or less, throughout your whole body.” “Oh, Henry!” exclaimed Mrs. Wilkinson, “How can you say such horrid things!” “Because they’re quite true, mamma—but you needn’t be frightened. The fire of one’s body is not hotter than from ninety degrees to one hundred and four degrees or so. Still it is fire, and will burn some things, as you would find, uncle, if, in using phosphorus, you were to let a little bit of it get under your nail.” “I’ll take your word for the fact, my boy,” said Mr. Bagges. “But, if I have a fire burning throughout my person—which I was not aware of, the only inflammation I am ever troubled with being in the great toe—I say, if my body is burning continually—how is it I don’t smoke—eh? Come, now?” “Perhaps you consume your own smoke,” suggested Mr. Wilkinson, senior, “like every well-regulated furnace.”