"To begin with," explained his companion, "I have to accomplish the most astonishing feats in the manner of speed. Literally I have to travel so fast that I am in two places at once. You will the better believe me when I tell you who I am,--Jack Frost, at your service, sir. Now, by what means do you think I manage it ?" "I 'm sure I don't know. I should like immensely to find out," Lionel returned. "How do you get to places yourself?" inquired Jack Frost. "Do you always run?" "Oh, no, indeed. I almost always ride on my bicycle. Then I can _go_ like anything, 'specially down _coasts_. Upgrades are kind of hard sometimes, but not so very. Oh, I can go quick enough when I have my bicycle." "Now then," broke in Jack Frost, "you use a bicycle,--that is, a machine having two wheels. Now _I_ use a something having but one wheel; consequently it goes twice as fast,--oh! much more than twice as fast." "One wheel?" repeated Lionel, thoughtfully; "seems to me I never heard of that kind of an one." "Suppose you guess," proposed Jack Frost. "I 'll put it in the form of a conundrum: If a thing having two wheels is called a _bi_cycle, what would a thing having but one be called?" "Oh, that's an old one. I 've heard that before, and the answer is, a wheelbarrow, you know." Jack Frost shook his head, "I see I shall have to tell you," he said. "If a thing having two wheels is called a _bi_cycle, a thing having but one would naturally be an _i_cicle. Of course you might have known I should use an icicle." "But oh, Mr. Frost," objected Lionel, "I never saw an icicle with a wheel in my life, and I never saw one go either." "That's because you have n't seen me on one; and even if you had seen me on one, you wouldn't have known it,--we travel so fast. Did you ever notice that when things are going at the very rapidest rate possible, they seem to be standing perfectly still? That's the way with icicles. They have tremendous speed in them. They go so fast you can't realize it, and then when they are slowing up they don't do it with a clumsy jerk as bicycles do; they just gradually melt out of sight." "Yes, I 've seen them do that. I 've seen them go that way," admitted Lionel. "But will you take me to the beggar? I'm 'fraid I sha'n't be able to give him his rule if I don't hurry up." "But do you know in what direction he went?" asked Jack Frost. "If one wants to catch up with any one, one needs to have _some_ idea of the direction he took. It's quite a _desideratum_,--when you get home, look that up." Then Lionel felt deeply mortified. "What a silly I was!" he said. "Perhaps I was going just the opposite way from the one he went. Oh, dear! how can I ever give him back his rule? It is such a beauty. If it had been mine, I 'd just hate to lose it."