"Perhaps I had better put it this way. Supposing you were to---- Well, we'd better begin further back than that. You know what---- No, I don't suppose you do know that. Well, if I--that is to say, when a man--you know, it's rather difficult to explain this, Margery." "Are you explaining it now?" "I'm just going to begin." "Thank you, Uncle." I lit my pipe slowly, while I considered again how best to approach the matter. "'Home Rails Firm,'" said Margery. "Isn't it a _funny_ thing to say?" It was. It was a very _silly_ thing to say. Whoever said it first might have known what it would lead to. "Perhaps I can explain it best like this, Margery," I said, beginning on a new tack. "I suppose you know what 'firm' means?" "What does it mean?" "Ah, well, if you don't know _that_," I said, rather pleased, "perhaps I had better explain that first. 'Firm' means that--that is to say, you call a thing firm if it--well, if it doesn't--that is to say, a thing is firm if it can't _move_." "Like a house?" "Well, something like that. This chair, for instance," and I put my hand on her chair, "is firm because you can't shake it. You see, it's quite---- Hallo, what's that?" "Oh, you bad Uncle, you've knocked the castor off again," cried Margery, greatly excited at the incident. "This is too much," I said bitterly. "Even the furniture is against me." "Go on explaining," said Margery, rocking herself in the now wobbly chair. I decided to leave "firm." It is not an easy word to explain at the best of times, and when everything you touch goes and breaks itself it becomes perfectly impossible. "Well, so much for that," I said. "And now we come to 'rails.' You know what rails are?" "Like I've got in the nursery?" This was splendid. I had forgotten these for the moment. "Exactly. The rails your train goes on. Well then, '_Home_ Rails' would be rails at _home_." "Well, I've _got_ them at home," said Margery in surprise. "I couldn't have them anywhere else." "Quite so. Then 'Home Rails Firm' would mean that--er--home rails were--er--firm." "But mine aren't, because they wobble. You know they do." "Yes, but----" "Well, why do they say 'Home Rails Firm' when they mean 'Home Rails Wobble'?" "Ah, that's just it. The point is that when they say 'Home Rails Firm,' they don't mean that the rails _themselves_ are firm. In fact, they don't mean at all what you think they mean. They mean something quite different." "What _do_ they mean?" "I am just going to explain," I said stiffly. . . . . . "Or perhaps I had better put it this way," I said ten minutes later. "Supposing---- Oh, Margery, it _is_ difficult to explain." "I _must_ know," said Margery. "_Why_ do you want to know so badly?" "I want to know a million million times more than anything else in the whole world." "Why?" "So as I can tell Angela," said Margery.