Ever since he was four years old, and had begun to think seriously, as a boy should, David Blaize had been aware that there was a real world lying somewhere just below the ordinary old thing in which his father and mother and nurse and the rest of the fast-asleep grown-up people lived. Boys began to get drowsy, he knew, about the time that they were ten, though they might still have occasional waking moments, and soon after that they went sound asleep, and lost all chance of ever seeing the real world. If you asked grown-ups some tremendously important question, such as ‘Why do the leaves fall off the trees when there is glass on the lake?’ as likely as not they would begin talking in their sleep about frost and sap, just as if that had got anything to do with the real reason. Or they might point out that it wasn’t real glass on the lake, but ice, and, if they were more than usually sound asleep, take a piece of the lake-glass and let you hold it in your fingers till it became water. That was to show you that what you had called glass was really frozen water, another word for which was ice. They thought that it was very wonderful of them to explain it all so nicely, and tell you at great length that real glass did not become water if you held it in your fingers, which you must remember to wash before dinner. Perhaps they would take you to the nursery window when you came in from your walk, and encourage you to put your finger on the pane in order to see that glass did not become water. This sort of thing would make David impatient, and he asked, ‘Then why don’t you put ice in the window, and then you could boil it for tea in the kettle?’ And if his nurse wanted to go to sleep again, she would say, ‘Now you’re talking nonsense, Master David.’ Now that was the ridiculous thing! Of course he was talking nonsense just to humour Nannie. He was helping her with her nonsense about the difference between ice and glass. He had been wanting to talk sense all the time, and learn something about the real world, in which the fish put a glass roof on their house for the winter as soon as they had collected enough red fire-leaves to keep them warm until the hot weather came round again. That might not be the precise way in which it happened, but it was something of that sort. Instead of pinching herself awake, poor sleepy Nannie went babbling on about ice and glass and sap and spring, in a way that was truly tedious and quite beside the real point.